String Handling

Fill in the blanks

Question 1

concat() method is used to join two strings.

Question 2

The output of the following statement, when executed:

System.out.println("COMPUTER".charAt(4)); is U

Question 3

The output of the statement, when executed:

System.out.println("Object Oriented".length()); is 15

Question 4

+ operator is used to concatenate two strings.

Question 5

String declaration is terminated by the symbol ;(semicolon).

Question 6

Character literal is enclosed within single quotes (').

Question 7

The return type of the statement equals( ) is boolean.

Question 8

The output of "VIDYALAYA."substring(2,5) will result in DYA

Write down the syntax to perform the following tasks

Question 1

To check whether a character(chr) is in upper case or not.

boolean res = Character.isUpperCase(chr);

Question 2

To compare two Strings(str1, str2) are same or not.

boolean res = str1.equals(str2);

Question 3

To extract the last character of a word(wd) stored in the variable chr.

char chr = wd.charAt(wd.length() - 1);

Question 4

To return the first occurrence of 'a' in the word "applications".

int res = "applications".indexOf('a');

Question 5

To replace the word "old" with the word "new" in a given String st = "old is always old"

String str = st.replace("old", "new");

Question 6

To check if the second character of a String(str) is in upper case.

boolean res = Character.isUpperCase(str.charAt(1));

Predict the output of the following

Question 1

String str = "Computer Applications" + 1 + 0;

System.out.println("Understanding" + str);

Output

UnderstandingComputer Applications10

Explanation

In the first line, + operator concatenates 1 and 0 to the end of "Computer Applications" so str becomes "Computer Applications10". Next line prints "UnderstandingComputer Applications10" to the console.

Question 2

String n1 = "46", n2 = "64";

int total = Integer.parseInt(n1) + Integer.parseInt(n2);

System.out.println("The sum of " + "46 " + "and" + " 64" + " is " + total);

Output

The sum of 46 and 64 is 110

Explanation

Integer.parseInt() method will convert the strings n1 and n2 to their corresponding numerical integers. So, 46 and 64 are added as numerical values and the result 110 is stored in int variable total.

Question 3

boolean p;

p = ("BLUEJ".length() > "bluej".length()) ? true: false;

Output

false

Explanation

Both "BLUEJ" and "bluej" have the same length 5. So, condition of ternary operator is false and false is assigned to boolean variable p.

Question 4

String str = "Information Technology";

int p;

p = str.indexOf('n');

System.out.println(p);

Output

1

Explanation

str.indexOf('n') will return the first index of n in str which is 1. So, the output of this program is 1.

Question 5

String str1 = "Information Technology";

String str2 = "information technology";

boolean p = str1.equalsIgnoreCase(str2);

System.out.println("The result is " + p);

Output

The result is true

Question 6

What do the following functions return?

String x = "Vision";

String y = "2020";

(a)

System.out.println(x + y);

Output

Vision2020

Explanation

x and y are concatenated and printed.

(b)

System.out.println(x.length());

Output

6

Explanation

x.length() will give the number of characters in string x which is 6.

(c)

System.out.println(x.charAt(3));

Output

i

(d)

System.out.println(x.equals(y));

Output

false

Question 7

String S1 = "Computer World";

String S2 = "COMPUTER WORLD";

String S3 = "Computer world";

String S4 = "computer world";

System.out.println(S1 + " equals "+ S2 + " " + S1.equals(S2));

System.out.println(S1 + " equals "+ S3 + " " + S1.equals(S3));

System.out.println(S1 + " equals "+ S4 + " " + S1.equals(S4));

System.out.println(S1 + " equalsIgnoreCase "+ S4 + " " + S1.equalsIgnoreCase(S4));

Output

Computer World equals COMPUTER WORLD false

Computer World equals Computer world false

Computer World equals computer world false

Computer World equalsIgnoreCase computer world true

Question 8

If:

String x = "Computer";

String y = "Applications";

What do the following functions return?

(i) System.out.println(x.substring(1,5));

Output

ompu

x.substring(1,5) will return a substring of x starting at index 1 till index 4 (i.e. 5 - 1 = 4).

(ii) System.out.println(x.indexOf(x.charAt(4)));

Output

4

(iii) System.out.println(y + x.substring(5));

Output

Applicationster

(iv) System.out.println(x.equals(y));

Output

false

Question 9

Give the output of the following:

String n = "Computer Knowledge";

String m = "Computer Applications";

System.out.println(n.substring(0,8).concat(m.substring(9)));

System.out.println(n.endsWith("e"));

Output

ComputerApplications

true

Question 10

Give the output of the following statements:

String x[] = {"SAMSUNG", "NOKIA", "SONY", "MICROMAX", "BLACKBERRY"};

(i) System.out.println(x[1]);

Output

NOKIA

Explanation

x[1] gives the second element of the array x which is "NOKIA"

(ii) System.out.println(x[3].length());

Output

8

Explanation

x[3].length() gives the number of characters in the fourth element of the array x.

Question 11

Give the output of the following string functions:

(i) "ACHIEVEMENT".replace('E', 'A')

Output

ACHIAVAMANT

Explanation

All 'E' are replaced with 'A'.

(ii) "DEDICATE".compareTo("DEVOTE")

Output

-18

Question 12

Consider the following String array and give the output

String arr[]= {"DELHI", "CHENNAI", "MUMBAI", "LUCKNOW", "JAIPUR"};

System.out.println(arr[0].length() > arr[3].length());

System.out.print(arr[4].substring(0,3));

Output

false

JAI

Differentiate between the following

Question 1

equals() and ==

equals()

• It is a method.

• It is used to check if the contents of two strings are same or not.

• Example:

String s1 = new String("hello");

String s2 = new String("hello");

boolean res = s1.equals(s2);

System.out.println(res);

==

• It is a relational operator.

• It is used to check if two variables refer to the same object in memory

• Example:

String s1 = new String("hello");

String s2 = new String("hello");

boolean res = s1 == s2;

System.out.println(res);

The output of this code snippet is false as s1 and s2 point to different String objects.

Question 2

compareTo() and equals()

compareTo()

• It compares two strings.The result is a negative, positive or zero integer value depending on whether the String object precedes, follows or is equal to the String argument

equals()

• It checks if contents of two strings are same or not.The result is true if the contents are same otherwise it is false.

Question 3

toLowerCase() and toUpperCase()

toLowerCase()

• Converts all characters of the String object to lower case

• Example:

String str = "HELLO";

System.out.println(str.toLowerCase());

toUpperCase()

• Converts all characters of the String object to upper case

• Example:

String str = "hello";

System.out.println(str.toUpperCase());

Output of this code snippet will be HELLO.

Question 4

charAt() and substring()

charAt()

• It returns a character from the string at the index specified as its argument

• Its return type is char

• Example:

String str = "Hello";

char ch = str.charAt(1);

System.out.println(ch);

substring()

• It extracts a part of the string as specified by its arguments and returns the extracted part as a new string.

• Its return type is String.

• Example:

String str = "Hello";

String subStr = str.substring(1);

System.out.println(subStr);

Write short answers

Question 1

What is exception? Name two exception handling blocks.

An exception is an event, which occurs during the execution of a program, that disrupts the normal flow of the program's instructions. Two exception handling blocks are try and catch.

Question 2

State the purpose and return data type of the following String functions:

(a) indexOf()

It returns the index within the string of the first occurrence of the specified character or -1 if the character is not present. Its return type is int.

(b) compareTo()

It compares two strings . Its return type is int.

Question 3

Write a statement for each to perform the following task on a string:

(i) Extract the second last character of a word stored in the variable wd.

char ch = wd.charAt(wd.length() - 2);

(ii) Check if the second character of a string str is in upper case.

boolean res = Character.isUpperCase(str.charAt(1));

Question 4

Write a statement each to perform the following task on a string:

(i) Find and display the position of the last space in a string s.

System.out.println(s.lastIndexOf(' '));

(ii) Convert a number stored in a string variable x to double data type.

double a = Double.parseDouble(x);

Question 5

How does endsWith() and startsWith() differ? Explain with an example.

endsWith() tests if the string object ends with the string specified as its argument. startsWith() tests if the string object starts with the string specified as its argument. Consider the below example:

public class Example {

public static void main(String args[]) {

String str = "ICSE Computer Applications";

System.out.println("Does " + str + " starts with ICSE? " + str.startsWith("ICSE"));

System.out.println("Does " + str + " ends with tions? " + str.endsWith("tions"));

}

}

Here, both str.startsWith("ICSE") and str.endsWith("tions") returns true as str starts with "ICSE" and ends with "tions".

Describe the purpose of the following functions with their syntax

Question 1

toUpperCase()

It converts a string into upper case characters. If any character is already in uppercase or is a special character then it will remain same.

Syntax:

String <variable-name> = <string-variable>.toUpperCase();

Question 2

trim()

It removes all leading and trailing space from the string.

Syntax:

String <variable-name> = <string-variable>.trim();

Question 3

toLowerCase()

It converts a string into lowercase characters. If any character is already in lowercase or is a special character then it will remain same.

Syntax:

String <variable-name> = <string-variable>.toLowerCase();

Question 4

length()

It returns the length of the string i.e. the number of characters present in the string.

Syntax:

int <variable-name> = <string-variable>.length();

Question 5

replace()

It replaces a character with another character or a substring with another substring at all its occurrences in the given string.

Syntax:

String <variable-name> = <string-variable>.replace(<character or substring to replace>, <new character or substring>);

Question 6

compareTo()

It compares two strings lexicographically.

Syntax:

int <variable-name> = <string-variable>.compareTo(<string-variable2>);

Question 7

reverse()

It is a method of StringBuffer class used to reverse the sequence of characters.

Syntax:

<StringBuffer-Variable>.reverse();

Question 8

indexOf()

It returns the index within the string of the first occurrence of the specified character or -1 if the character is not present.

Syntax:

int <variable-name> = <string-variable>.indexOf(<character>);

Question 9

startWith()

It tests if the string object starts with the string specified as its argument.

Syntax:

boolean <variable-name> = <string-variable>.startWith(<string>);

Question 10

equalsIgnoreCase()

It ignores the case of the characters and checks if the contents of two strings are same or not.

Syntax:

boolean <variable-name> = <string-variable>.equalsIgnoreCase(<string>);

Solutions to Unsolved Java Programs

Question 1

Write a program to input a sentence. Find and display the following:

(i) Number of words present in the sentence

(ii) Number of letters present in the sentence

Assume that the sentence has neither include any digit nor a special character.

import java.util.Scanner;

public class WordsNLetters

{

public static void main(String args[]) {

Scanner in = new Scanner(System.in);

System.out.println("Enter a sentence:");

String str = in.nextLine();

int wCount = 0, lCount = 0;

int len = str.length();

for (int i = 0; i < len; i++) {

char ch = str.charAt(i);

if (ch == ' ')

wCount++;

else

lCount++;

}

/*

* Number of words in a sentence are one more than

* the number of spaces so incrementing wCount by 1

*/

wCount++;

System.out.println("No. of words = " + wCount);

System.out.println("No. of letters = " + lCount);

}

}

Question 2

Write a program in Java to accept a word/a String and display the new string after removing all the vowels present in it.

Sample Input: COMPUTER APPLICATIONS

Sample Output: CMPTR PPLCTNS

import java.util.Scanner;

public class VowelRemoval

{

public static void main(String args[]) {

Scanner in = new Scanner(System.in);

System.out.println("Enter a word or sentence:");

String str = in.nextLine();

int len = str.length();

String newStr = "";

for (int i = 0; i < len; i++) {

char ch = Character.toUpperCase(str.charAt(i));

if (ch == 'A' ||

ch == 'E' ||

ch == 'I' ||

ch == 'O' ||

ch == 'U') {

continue;

}

newStr = newStr + ch;

}

System.out.println("String with vowels removed");

System.out.println(newStr);

}

}

Question 3

Write a program in Java to accept a name(Containing three words) and Display only the initials (i.e., first letter of each word).

Sample Input: LAL KRISHNA ADVANI

Sample Output: L K A

import java.util.Scanner;

public class NameInitials

{

public static void main(String args[]) {

Scanner in = new Scanner(System.in);

System.out.println("Enter a name of 3 or more words:");

String str = in.nextLine();

int len = str.length();

System.out.print(str.charAt(0) + " ");

for (int i = 1; i < len; i++) {

char ch = str.charAt(i);

if (ch == ' ') {

char ch2 = str.charAt(i + 1);

System.out.print(ch2 + " ");

}

}

}

}

Output

Question 4

Write a program in Java to accept a name containing three words and display the surname first, followed by the first and middle names.

Sample Input: MOHANDAS KARAMCHAND GANDHI

Sample Output: GANDHI MOHANDAS KARAMCHAND

import java.util.Scanner;

public class SurnameFirst

{

public static void main(String args[]) {

Scanner in = new Scanner(System.in);

System.out.println("Enter a name of 3 words:");

String name = in.nextLine();

/*

* Get the last index

* of space in the string

*/

int lastSpaceIdx = name.lastIndexOf(' ');

String surname = name.substring(lastSpaceIdx + 1);

String initialName = name.substring(0, lastSpaceIdx);

System.out.println(surname + " " + initialName);

}

}

Question 5

Write a program in Java to enter a String/Sentence and display the longest word and the length of the longest word present in the String.

Sample Input: “TATA FOOTBALL ACADEMY WILL PLAY AGAINST MOHAN BAGAN”

Sample Output: The longest word: FOOTBALL: The length of the word: 8

import java.util.Scanner;

public class LongestWord

{

public static void main(String args[]) {

Scanner in = new Scanner(System.in);

System.out.println("Enter a word or sentence:");

String str = in.nextLine();

str += " "; //Add space at end of string

String word = "", lWord = "";

int len = str.length();

for (int i = 0; i < len; i++) {

char ch = str.charAt(i);

if (ch == ' ') {

if (word.length() > lWord.length())

lWord = word;

word = "";

}

else {

word += ch;

}

}

System.out.println("The longest word: " + lWord +

": The length of the word: " + lWord.length());

}

}

Output

Question 6

Write a program in Java to accept a word and display the ASCII code of each character of the word.

Sample Input: BLUEJ

Sample Output:

ASCII of B = 66

ASCII of L = 76

ASCII of U = 85

ASCII of E = 69

ASCII of J = 74

import java.util.Scanner;

public class ASCIICode

{

public static void main(String args[]) {

Scanner in = new Scanner(System.in);

System.out.println("Enter a word:");

String word = in.nextLine();

int len = word.length();

for (int i = 0; i < len; i++) {

char ch = word.charAt(i);

System.out.println("ASCII of " + ch

+ " = " + (int)ch);

}

}

}

Output

Question 7

Write a program in Java to accept a String in upper case and replace all the vowels present in the String with Asterisk (*) sign.

Sample Input: "TATA STEEL IS IN JAMSHEDPUR"

Sample output: T*T* ST**L *S *N J*MSH*DP*R

import java.util.Scanner;

public class VowelReplace

{

public static void main(String args[]) {

Scanner in = new Scanner(System.in);

System.out.println("Enter a string in uppercase:");

String str = in.nextLine();

String t = str.toUpperCase();

String newStr = "";

int len = t.length();

for (int i = 0; i < len; i++) {

char ch = str.charAt(i);

if (ch == 'A' ||

ch == 'E' ||

ch == 'I' ||

ch == 'O' ||

ch == 'U') {

newStr = newStr + '*';

}

else {

newStr = newStr + ch;

}

}

System.out.println(newStr);

}

}

Output

Question 8

Write a program in Java to enter a sentence. Frame a word by joining all the first characters of each word of the sentence. Display the word.

Sample Input: Vital Information Resource Under Seize

Sample Output: VIRUS

import java.util.Scanner;

public class FrameWord

{

public static void main(String args[]) {

Scanner in = new Scanner(System.in);

System.out.println("Enter a sentence:");

String str = in.nextLine();

String word = "" + str.charAt(0);

int len = str.length();

for (int i = 0; i < len; i++) {

char ch = str.charAt(i);

if (ch == ' ')

word += str.charAt(i + 1);

}

System.out.println(word);

}

}

Output

Question 9

Write a program in Java to enter a sentence. Display the words which are only palindrome.

Sample Input: MOM AND DAD ARE NOT AT HOME

Sample Output: MOM

DAD

import java.util.Scanner;

public class PalinWords

{

public static void main(String args[]) {

Scanner in = new Scanner(System.in);

System.out.println("Enter a sentence:");

String str = in.nextLine();

str = str + " ";

String word = "";

int len = str.length();

for (int i = 0; i < len; i++) {

char ch = str.charAt(i);

if (ch == ' ') {

int wordLen = word.length();

boolean isPalin = true;

for (int j = 0; j < wordLen / 2; j++) {

if (word.charAt(j) != word.charAt(wordLen - 1 - j)) {

isPalin = false;

break;

}

}

if (isPalin)

System.out.println(word);

word = "";

}

else {

word += ch;

}

}

}

}

Output

Question 10

Write a program to accept a sentence. Display the sentence in reversing order of its word.

Sample Input: Computer is Fun

Sample Output: Fun is Computer

import java.util.Scanner;

public class ReverseWords

{

public static void main(String args[]) {

Scanner in = new Scanner(System.in);

System.out.println("Enter a sentence:");

String str = in.nextLine();

str = " " + str;

String word = "";

int len = str.length();

for (int i = len - 1; i >= 0; i--) {

char ch = str.charAt(i);

if (ch == ' ') {

System.out.print(word + " ");

word = "";

}

else {

word = ch + word;

}

}

}

}

Output

Question 11

Write a program to input a sentence and display the word of the sentence that contains maximum number of vowels.

Sample Input: HAPPY NEW YEAR

Sample Output: The word with maximum number of vowels: YEAR

import java.util.Scanner;

public class MaxVowelWord

{

public static void main(String args[]) {

Scanner in = new Scanner(System.in);

System.out.println("Enter a sentence:");

String str = in.nextLine();

str = str + " ";

String word = "", mWord = "";

int count = 0, maxCount = 0;

int len = str.length();

for (int i = 0; i < len; i++) {

char ch = Character.toUpperCase(str.charAt(i));

if (ch == 'A' ||

ch == 'E' ||

ch == 'I' ||

ch == 'O' ||

ch == 'U') {

count++;

}

if (ch == ' ') {

if (count > maxCount) {

maxCount = count;

mWord = word;

}

word = "";

count = 0;

}

else {

word += ch;

}

}

System.out.println("The word with maximum number of vowels: "

+ mWord);

}

}

Output

Question 12

Consider the sentence as given below:

Blue bottle is in Blue bag lying on Blue carpet

Write a program to assign the given sentence to a string variable. Replace the word Blue with Red at all its occurrence. Display the new string as shown below:

Red bottle is in Red bag lying on Red carpet

public class StringReplace

{

public static void main(String args[]) {

String str = "Blue bottle is in Blue bag lying on Blue carpet";

str += " ";

String newStr = "";

String word = "";

String target = "Blue";

String newWord = "Red";

int len = str.length();

for (int i = 0; i < len; i++) {

char ch = str.charAt(i);

if (ch == ' ') {

if (target.equals(word)) {

newStr = newStr + newWord + " ";

}

else {

newStr = newStr + word + " ";

}

word = "";

}

else {

word += ch;

}

}

System.out.println(newStr);

}

}

Question 13

Write a program to accept a word and convert it into lower case, if it is in upper case. Display the new word by replacing only the vowels with the letter following it.

Sample Input: computer

Sample Output: cpmpvtfr

import java.util.Scanner;

public class VowelReplace

{

public static void main(String args[]) {

Scanner in = new Scanner(System.in);

System.out.print("Enter a word: ");

String str = in.nextLine();

str = str.toLowerCase();

String newStr = "";

int len = str.length();

for (int i = 0; i < len; i++) {

char ch = str.charAt(i);

if (str.charAt(i) == 'a' ||

str.charAt(i) == 'e' ||

str.charAt(i) == 'i' ||

str.charAt(i) == 'o' ||

str.charAt(i) == 'u') {

char nextChar = (char)(ch + 1);

newStr = newStr + nextChar;

}

else {

newStr = newStr + ch;

}

}

System.out.println(newStr);

}

}

Question 14

A string is said to be ‘Unique’ if none of the letters present in the string are repeated. Write a program to accept a string and check whether the string is Unique or not. The program displays a message accordingly.

Sample Input: COMPUTER

Sample Output: Unique String

import java.util.Scanner;

public class UniqueString

{

public static void main(String args[]) {

Scanner in = new Scanner(System.in);

System.out.print("Enter a string: ");

String str = in.nextLine();

str = str.toUpperCase();

boolean isUnique = true;

int len = str.length();

for (int i = 0; i < len; i++) {

char ch = str.charAt(i);

for (int j = i + 1; j < len; j++) {

if (ch == str.charAt(j)) {

isUnique = false;

break;

}

}

if (!isUnique)

break;

}

if (isUnique)

System.out.println("Unique String");

else

System.out.println("Not Unique String");

}

}

Question 15

A 'Happy Word' is defined as:

Take a word and calculate the word’s value based on position of the letters in English alphabet. On the basis of word’s value, find the sum of the squares of its digits. Repeat the process with the resultant number until the number equals 1 (one). If the number ends with 1 then the word is called a 'Happy Word'.

Write a program to input a word and check whether it a ‘Happy Word’ or not. The program displays a message accordingly.

Sample Input: VAT

Place value of V = 22, A= 1, T = 20

[Hint: A = 1, B = 2, ----------, Z = 26]

Solution:

22120 ⇒ 2² + 2² + 1² + 2² + 0² = 13

⇒ 1² + 3² = 10

⇒ 1² + 0² = 1

Sample Output: A Happy Word

import java.util.Scanner;

public class HappyWord

{

private static boolean isHappyNumber(long num) {

long sum = 0;

long n = num;

do {

sum = 0;

while (n != 0) {

int d = (int)(n % 10);

sum += d * d;

n /= 10;

}

n = sum;

} while (sum > 6);

return (sum == 1);

}

public static void main(String args[]) {

Scanner in = new Scanner(System.in);

System.out.println("Enter a word: ");

String word = in.next();

word = word.toUpperCase();

String wordValueStr = "";

int len = word.length();

for (int i = 0; i < len; i++) {

wordValueStr += String.valueOf(word.charAt(i) - 64);

}

long wordValue = Long.parseLong(wordValueStr);

boolean isHappy = isHappyNumber(wordValue);

if (isHappy)

System.out.println("A Happy Word");

else

System.out.println("Not a Happy Word");

}

}

Question 16

Write a program to input a sentence. Count and display the frequency of each letter of the sentence in alphabetical order.

import java.util.Scanner;

public class LetterFreq

{

public static void main(String args[]) {

Scanner in = new Scanner(System.in);

System.out.println("Enter a sentence:");

String str = in.nextLine();

str = str.toUpperCase();

int freqMap[] = new int[26];

int len = str.length();

for (int i = 0; i < len; i++) {

char ch = str.charAt(i);

if (Character.isLetter(ch)) {

int chIdx = ch - 65;

freqMap[chIdx]++;

}

}

System.out.println("Character\tFrequency");

for (int i = 0; i < freqMap.length; i++) {

if (freqMap[i] > 0) {

System.out.println((char)(i + 65)

+ "\t\t" + freqMap[i]);

}

}

}

}

Question 17

Write a program to accept a string. Convert the string into upper case letters. Count and output the number of double letter sequences that exist in the string.

Sample Input: "SHE WAS FEEDING THE LITTLE RABBIT WITH AN APPLE"

Sample Output: 4

import java.util.Scanner;

public class LetterSeq

{

public static void main(String args[]) {

Scanner in = new Scanner(System.in);

System.out.print("Enter string: ");

String s = in.nextLine();

String str = s.toUpperCase();

int count = 0;

int len = str.length();

for (int i = 0; i < len - 1; i++) {

if (str.charAt(i) == str.charAt(i + 1))

count++;

}

System.out.println("Double Letter Sequence Count = " + count);

}

}

Question 18

Special words are those words which start and end with the same letter.

Example: EXISTENCE, COMIC, WINDOW

Palindrome words are those words which read the same from left to right and vice-versa.

Example: MALYALAM, MADAM, LEVEL, ROTATOR, CIVIC

All palindromes are special words but all special words are not palindromes.

Write a program to accept a word. Check and display whether the word is a palindrome or only a special word or none of them.

import java.util.Scanner;

public class SpecialPalindrome

{

public static void main(String args[]) {

Scanner in = new Scanner(System.in);

System.out.print("Enter a word: ");

String str = in.next();

str = str.toUpperCase();

int len = str.length();

if (str.charAt(0) == str.charAt(len - 1)) {

boolean isPalin = true;

for (int i = 1; i < len / 2; i++) {

if (str.charAt(i) != str.charAt(len - 1 - i)) {

isPalin = false;

break;

}

}

if (isPalin) {

System.out.println("Palindrome");

}

else {

System.out.println("Special");

}

}

else {

System.out.println("Neither Special nor Palindrome");

}

}

}

Question 19

Write a program to input a sentence. Convert the sentence into upper case letters. Display the words along with frequency of the words which have at least a pair of consecutive letters.

Sample Input: MODEM IS AN ELECTRONIC DEVICE

Sample Output:

MODEM

DEVICE

Number of words containing consecutive letters: 2

import java.util.Scanner;

public class StringConsecutive

{

public static void main(String args[]) {

Scanner in = new Scanner(System.in);

System.out.print("Enter the string: ");

String str = in.nextLine();

str = str.toUpperCase();

str += " ";

String word = "";

int count = 0;

int len = str.length();

for (int i = 0; i < len; i++) {

if (str.charAt(i) == ' ') {

int wordLen = word.length();

for (int j = 0; j < wordLen - 1; j++) {

if (word.charAt(j) + 1 == word.charAt(j + 1)) {

count++;

System.out.println(word);

break;

}

}

word = "";

}

else {

word += str.charAt(i);

}

}

System.out.println("Number of words containing consecutive letters: " + count);

}

}

Question 20

Write a program to accept a word (say, BLUEJ) and display the pattern:

(a)

B L U E J

B L U E

B L U

B L

B

import java.util.Scanner;

public class StringPattern

{

public static void main(String args[]) {

Scanner in = new Scanner(System.in);

System.out.print("Enter a word: ");

String word = in.nextLine();

int len = word.length();

for (int i = len - 1; i >= 0; i--) {

for (int j = 0; j <= i; j++) {

char ch = word.charAt(j);

System.out.print(ch);

}

System.out.println();

}

}

}

(b)

J

E E

U U U

L L L L

B B B B B

import java.util.Scanner;

public class StringPattern

{

public static void main(String args[]) {

Scanner in = new Scanner(System.in);

System.out.print("Enter a word: ");

String word = in.nextLine();

int len = word.length();

for (int i = len - 1; i >= 0; i--) {

for (int j = len - 1; j >= i; j--) {

char ch = word.charAt(i);

System.out.print(ch);

}

System.out.println();

}

}

}

(c)

B L U E J

L U E J

U E J

E J

J

import java.util.Scanner;

public class StringPattern

{

public static void main(String args[]) {

Scanner in = new Scanner(System.in);

System.out.print("Enter a word: ");

String word = in.nextLine();

int len = word.length();

for (int i = 0; i < len; i++) {

for (int j = i; j < len; j++) {

char ch = word.charAt(j);

System.out.print(ch);

}

System.out.println();

}

}

}

Question 21

Write a program to display the pattern:

(a)

A B C D E

B C D E

C D E

D E

E

public class StringPattern

{

public static void main(String args[]) {

String word = "ABCDE";

int len = word.length();

for (int i = 0; i < len; i++) {

for (int j = i; j < len; j++) {

char ch = word.charAt(j);

System.out.print(ch);

}

System.out.println();

}

}

}

(b)

A

B C

D E F

G H I J

K L M N O

public class StringPattern

{

public static void main(String args[]) {

char ch = 'A';

for (int i = 0; i < 5; i++) {

for (int j = 0; j <= i; j++) {

System.out.print(ch++);

}

System.out.println();

}

}

}

(c)

A B C D E

A B C D A

A B C A B

A B A B C

A A B C D

public class StringPattern

{

public static void main(String args[]) {

String word = "ABCDE";

int len = word.length();

for (int i = 0; i < len; i++) {

for (int j = 0; j < len - i; j++) {

System.out.print(word.charAt(j));

}

for (int k = 0; k < i; k++) {

System.out.print(word.charAt(k));

}

System.out.println();

}

}

}

Question 22

Write a program to generate a triangle or an inverted triangle till n terms based upon the User’s choice of the triangle to be displayed.

Example 1:

Input: Type 1 for a triangle and

Type 2 for an inverted triangle

Enter your choice 1

Enter the number of terms 5

Sample Output:

* * * * *

* * * *

* * *

* *

*

Example 2:

Input: Type 1 for a triangle and

Type 2 for an inverted triangle

Enter your choice 2

Enter the number of terms 5

Sample Output:

A B C D E

A B C D

A B C

A B

A

import java.util.Scanner;

public class TriangleChoice

{

public static void main(String args[]) {

Scanner in = new Scanner(System.in);

System.out.println("Type 1 for a triangle and");

System.out.println("Type 2 for an inverted triangle of alphabets");

System.out.print("Enter your choice: ");

int choice = in.nextInt();

System.out.print("Enter the number of terms: ");

int n = in.nextInt();

switch (choice) {

case 1:

for (int i = 0; i <= n; i++) {

for (int j = 0; j < i; j++) {

System.out.print(' ');

}

for (int k = i; k <= n; k++) {

System.out.print('*');

}

System.out.println();

}

break;

case 2:

n += 64;

for (int i = n; i >= 65; i--) {

for (int j = 65; j <= i; j++) {

System.out.print((char)j);

}

System.out.println();

}

break;

default:

System.out.println("Incorrect choice");

break;

}

}

}

Question 23

Write a program to generate a triangle or an inverted triangle based upon User’s choice.

Example 1:

Input: Type 1 for a triangle and

Type 2 for an inverted triangle

Enter your choice 1

Enter a word : BLUEJ

Sample Output:

B

L L

U U U

E E E E

J J J J J

Example 2:

Input: Type 1 for a triangle and

Type 2 for an inverted triangle

Enter your choice 2

Enter a word : BLUEJ

Sample Output:

B L U E J

B L U E

B L U

B L

B

import java.util.Scanner;

public class TriangleMenu

{

public static void main(String args[]) {

Scanner in = new Scanner(System.in);

System.out.println("Type 1 for a triangle and");

System.out.println("Type 2 for an inverted triangle");

System.out.print("Enter your choice: ");

int choice = in.nextInt();

in.nextLine();

System.out.print("Enter a word: ");

String word = in.nextLine();

int len = word.length();

switch (choice) {

case 1:

for(int i = 0; i < len; i++) {

for(int j = 0; j <= i; j++) {

System.out.print(word.charAt(i));

}

System.out.println();

}

break;

case 2:

for(int i = len - 1; i >= 0; i--) {

for(int j = 0; j <= i; j++) {

System.out.print(word.charAt(j));

}

System.out.println();

}

break;

default:

System.out.println("Incorrect choice");

break;

}

}

}

Question 24

Using the switch statement, write a menu driven program for the following:

(a) To print the Floyd’s triangle:

1

2 3

4 5 6

7 8 9 10

11 12 13 14 15

(b) To display the following pattern:

I

I C

I C S

I C S E

For an incorrect option, an appropriate error message should be displayed.

import java.util.Scanner;

public class Pattern

{

public static void main(String args[]) {

Scanner in = new Scanner(System.in);

System.out.println("Type 1 for Floyd's triangle");

System.out.println("Type 2 for an ICSE pattern");

System.out.print("Enter your choice: ");

int ch = in.nextInt();

switch (ch) {

case 1:

int a = 1;

for (int i = 1; i <= 5; i++) {

for (int j = 1; j <= i; j++) {

System.out.print(a++ + "\t");

}

System.out.println();

}

break;

case 2:

String s = "ICSE";

for (int i = 0; i < s.length(); i++) {

for (int j = 0; j <= i; j++) {

System.out.print(s.charAt(j) + " ");

}

System.out.println();

}

break;

default:

System.out.println("Incorrect Choice");

}

}

}

Question 25

Write a program in Java to store 10 different country names and their capitals in two different Single Dimensional Arrays (SDA). Display the country names (that starts with a vowel) along with their capitals in the given format.

Country Names Capital

xxxx xxxx

xxxx xxxx

import java.util.Scanner;

public class CountryCapital

{

public static void main(String args[]) {

final int SIZE = 10;

Scanner in = new Scanner(System.in);

String countries[] = new String[SIZE];

String capitals[] = new String[SIZE];

System.out.println("Enter " + SIZE

+ " countries and their capitals");

for (int i = 0; i < SIZE; i++) {

System.out.print("Enter country name: ");

countries[i] = in.nextLine();

System.out.print("Enter its capital: ");

capitals[i] = in.nextLine();

}

System.out.println("Country Names\t\tCapital");

for (int i = 0; i < SIZE; i++) {

char ch = Character.toUpperCase(countries[i].charAt(0));

if (ch == 'A' ||

ch == 'E' ||

ch == 'I' ||

ch == 'O' ||

ch == 'U') {

System.out.println(countries[i] + "\t\t" + capitals[i]);

}

}

}

}

Question 26

(a) Write a program in Java to store 20 different names and telephone numbers of your friends in two different Single Dimensional Arrays (SDA). Now arrange all the names in alphabetical order and display all the names along with their respective telephone numbers using selection sort technique.

import java.util.Scanner;

public class TelephoneBook

{

public static void main(String args[]) {

final int SIZE = 20;

Scanner in = new Scanner(System.in);

String names[] = new String[SIZE];

long telNos[] = new long[SIZE];

System.out.println("Enter " + SIZE + " names and telephone numbers");

for (int i = 0; i < SIZE; i++) {

System.out.print("Enter Name: ");

names[i] = in.nextLine();

System.out.print("Enter telephone number: ");

telNos[i] = in.nextLong();

in.nextLine();

}

//Selection Sort

for (int i = 0; i < SIZE - 1; i++) {

int min = i;

for (int j = i + 1; j < SIZE; j++) {

if (names[j].compareToIgnoreCase(names[min]) < 0) {

min = j;

}

}

String temp = names[min];

names[min] = names[i];

names[i] = temp;

long t = telNos[min];

telNos[min] = telNos[i];

telNos[i] = t;

}

System.out.println("Name\tTelephone Number");

for (int i = 0; i < SIZE; i++) {

System.out.println(names[i] + "\t" + telNos[i]);

}

}

}

(b) Write a program to accept 10 names in a Single Dimensional Array (SDA). Display the names whose first letter matches with the letter entered by the user.

Sample Input:

Aman Shahi

Akash Gupta

Suman Mishra

and so on ..........

Sample Output:

Enter the alphabet: A

Aman Shahi

Akash Gupta

.....

.....

import java.util.Scanner;

public class Names

{

public static void main(String args[]) {

Scanner in = new Scanner(System.in);

String names[] = new String[10];

System.out.println("Enter 10 names");

for (int i = 0; i < names.length; i++) {

names[i] = in.nextLine();

}

System.out.print("Enter a letter: ");

char ch = in.next().charAt(0);

ch = Character.toUpperCase(ch);

for (int i = 0; i < names.length; i++) {

if (Character.toUpperCase(names[i].charAt(0)) == ch) {

System.out.println(names[i]);

}

}

}

}

Question 27

Write a program to input twenty names in an array. Arrange these names in ascending order of letters, using the bubble sort technique.

Sample Input:

Rohit, Devesh, Indrani, Shivangi, Himanshu, Rishi, Piyush, Deepak, Abhishek, Kunal, .....

Sample Output:

Abhishek, Deepak, Devesh, Himanshu, Indrani, Kunal, Piyush, Rishi, Rohit, Shivangi, .....

import java.util.Scanner;

public class ArrangeNames

{

public static void main(String args[]) {

Scanner in = new Scanner(System.in);

String names[] = new String[20];

System.out.println("Enter 20 names:");

for (int i = 0; i < names.length; i++) {

names[i] = in.nextLine();

}

//Bubble Sort

for (int i = 0; i < names.length - 1; i++) {

for (int j = 0; j < names.length - 1 - i; j++) {

if (names[j].compareToIgnoreCase(names[j + 1]) > 0) {

String temp = names[j + 1];

names[j + 1] = names[j];

names[j] = temp;

}

}

}

System.out.println("\nSorted Names");

for (int i = 0; i < names.length; i++) {

System.out.println(names[i]);

}

}

}

Question 28

Write a program in Java to input the names of 10 cities in a Single Dimensional Array. Display only those names which begin with a consonant but end with a vowel.

Sample Input: Kolkata, Delhi, Bengaluru, Jamshedpur, Bokaro, .......

Sample Output: Kolkata

Delhi

Bengaluru

Bokaro

....

....

import java.util.Scanner;

public class CityName

{

public static boolean isVowel(char ch) {

char letter = Character.toUpperCase(ch);

if (letter == 'A' ||

letter == 'E' ||

letter == 'I' ||

letter == 'O' ||

letter == 'U')

return true;

return false;

}

public static void main(String args[]) {

String cities[] = new String[10];

Scanner in = new Scanner(System.in);

System.out.println("Enter 10 city names");

for (int i = 0; i < cities.length; i++) {

cities[i] = in.nextLine();

}

System.out.println("\nCities starting with consonant & ending with vowel:");

for (int i = 0; i < cities.length; i++) {

if (!isVowel(cities[i].charAt(0)) &&

isVowel(cities[i].charAt(cities[i].length() - 1)))

System.out.println(cities[i]);

}

}

}

Question 29

Write a program in Java to store 10 words in a Single Dimensional Array. Display only those words which are Palindrome.

Sample Input: MADAM, TEACHER, SCHOOL, ABBA, .........

Sample Output: MADAM

ABBA

..........

..........

import java.util.Scanner;

public class Palindrome

{

public static void main(String args[]) {

Scanner in = new Scanner(System.in);

String words[] = new String[10];

System.out.println("Enter 10 words:");

for (int i = 0; i < words.length; i++) {

words[i] = in.nextLine();

}

System.out.println("\nPalindrome Words:");

for (int i = 0; i < words.length; i++) {

String str = words[i].toUpperCase();

int strLen = str.length();

boolean isPalin = true;

for (int j = 0; j < strLen / 2; j++) {

if (str.charAt(j) != str.charAt(strLen - 1 - j)) {

isPalin = false;

break;

}

}

if (isPalin)

System.out.println(words[i]);

}

}

}

Question 30

Write a program to accept the names of 10 cities in a single dimensional string array and their STD (Subscribers Trunk Dialling) codes in another single dimension integer array. Search for the name of a city input by the user in the list. If found, display "Search Successful" and print the name of the city along with its STD code, or else display the message "Search unsuccessful, no such city in the list".

import java.util.Scanner;

public class StdCodes

{

public static void main(String args[]) {

final int SIZE = 10;

Scanner in = new Scanner(System.in);

String cities[] = new String[SIZE];

String stdCodes[] = new String[SIZE];

System.out.println("Enter " + SIZE +

" cities and their STD codes:");

for (int i = 0; i < SIZE; i++) {

System.out.print("Enter City Name: ");

cities[i] = in.nextLine();

System.out.print("Enter its STD Code: ");

stdCodes[i] = in.nextLine();

}

System.out.print("Enter name of city to search: ");

String city = in.nextLine();

int idx;

for (idx = 0; idx < SIZE; idx++) {

if (city.compareToIgnoreCase(cities[idx]) == 0) {

break;

}

}

if (idx < SIZE) {

System.out.println("Search Successful");

System.out.println("City: " + cities[idx]);

System.out.println("STD Code: " + stdCodes[idx]);

}

else {

System.out.println("Search Unsuccessful");

}

}

}