Answer the following questions

Question 1

What is a package?

In Java, a package is used to group related classes. Packages are of 2 types:

1. Built-In packages — These are provided by Java API

2. User-Defined packages — These are created by the programmers to efficiently structure their code.
   java.util, java.lang are a couple of examples of built-in packages.

Question 2

What is the significance of '*' while importing a package?

The asterisk(*) sign indicates that all the classes in the imported package can be used in the program.

Question 3

Define a wrapper class.

Wrapper classes wrap the value of a primitive type in an object. Wrapper classes are present in java.lang package. The different wrapper classes provided by Java are Boolean, Byte, Integer, Float, Character, Short, Long and Double.

Question 4

Differentiate between:

(a) isUpperCase() and toUpperCase()

isUpperCase()

• It is used to check if the character given as its argument is in upper case or not.

• Its return type is boolean

toUpperCase()

• It is used to convert the character given as its argument to upper case

• Its return type is char

(b) parseInt() and toString() functions

parseInt()

• It converts a string to an integer

• Its return type is int

toString()

• It converts an integer to a string

• Its return type is String

(c) primitive type and composite type data

Primitive Data Types

• Primitive Data Types are Java's fundamental data types

• Primitive Data Types are built-in data types defined by Java language specification

• Examples of Primitive Data Types are byte, short, int, long, float, double, char, boolean

Composite Data Types

• Composite Data Types are created by using Primitive Data Types

• Composite Data Types are defined by the programmer

• Examples of Composite Data Types are Class and Array

Question 5(i)

int res = 'A';

What is the value of res?

Value of res is 65.

Question 5(ii)

Name the package that contains wrapper classes.

java.lang

Question 5(iii)

Write the prototype of a function check which takes an integer as an argument and returns a character.

char check(int n)

Write the purpose of the following functions

Question 1

Float.parseFloat()

It is used to convert string data into float data.

Question 2

Double.toString()

It is used to convert double data to a string.

Question 3

Integer.valueOf()

It is used to convert string data into the Integer wrapper object.

Question 4

Character.isDigit()

It is used to check if the character given as its argument is a digit.

Question 5

Character.isWhitespace()

It is used to check if the character given as its argument is a whitespace.

Find the output of the following program snippets

Question 1

char ch = '*';

boolean b = Character.isLetter(ch);

System.out.println(b);

Output

false

Question 2

char c = 'A';

int n = (int) c + 32;

System.out.println((char)n);

Output

a

Question 3

String s= "7";

int t =Integer.parseInt(s);

t=t+1000;

System.out.println(t);

Output

1007

Question 4

char c = 'B';

int i = 4;

System.out.println(c+i);

System.out.println((int)c+i);

Output

70

70

Question 5

char ch = 'y';

char chr = Character.toUpperCase(ch);

int p = (int) chr;

System.out.println(chr + "\t" + p);

Output

Y 89

Question 6

int n = 97;

char ch = Character.toUpperCase((char)n);

System.out.println(ch + " Great Victory");

Output

A Great Victory

Question 7

char ch = 'x'; int n = 5;

n = n + (int)ch;

char c = (char)n;

System.out.println((char)((int)c-26));

Output

c

Question 8

char ch = 'A';

char chr = Character.toLowerCase(ch);

int n = (int)chr-32;

System.out.println((char)n + "\t" + chr);

Output

A a

Solutions to Unsolved Java Programs

Question 1

Write a program in Java to input a character. Find and display the next 10^th character in the ASCII table.

import java.util.Scanner;

public class TenthChar

{

public static void main(String [] args) {

Scanner in = new Scanner(System.in);

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

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

char nextCh = (char)(ch + 10);

System.out.println("Tenth character from "

+ ch + " is " + nextCh);

}

}

Question 2

Write a program in Java to input a character. Display next 5 characters.

import java.util.Scanner;

public class FiveChars

{

public static void main(String [] args) {

Scanner in = new Scanner(System.in);

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

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

System.out.println("Next 5 characters from "

+ ch + " are:");

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

System.out.println(++ch);

}

}

}

Question 3

Write a program in Java to generate all the alternate letters in the range of letters from A to Z.

public class AlternateLetters

{

public static void main(String [] args) {

for (char ch = 'A'; ch <= 'Z'; ch = (char)(ch + 2)) {

System.out.println(ch);

}

}

}

Question 4

Write a program to input a set of 20 letters. Convert each letter into upper case. Find and display the number of vowels and number of consonants present in the set of given letters.

import java.util.Scanner;

public class LetterSet

{

public static void main(String [] args) {

Scanner in = new Scanner(System.in);

System.out.println("Enter any 20 letters");

int vc = 0, cc = 0;

for (int i = 0; i < 20; i++) {

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

ch = Character.toUpperCase(ch);

if (ch == 'A' ||

ch == 'E' ||

ch == 'I' ||

ch == 'O' ||

ch == 'U')

vc++;

else if (ch >= 'A' && ch <= 'Z')

cc++;

}

System.out.println("Number of Vowels = " + vc);

System.out.println("Number of Consonants = " + cc);

}

}

Question 5

Write a program in Java to accept an integer number N such that 0<N<27. Display the corresponding letter of the alphabet (i.e. the letter at position N).

[Hint: If N =1 then display A]

import java.util.Scanner;

public class tInteger2Letter

{

public static void main(String [] args) {

Scanner in = new Scanner(System.in);

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

int n = in.nextInt();

if (n > 0 && n < 27) {

char ch = (char)(n + 64);

System.out.println("Corresponding letter = " + ch);

}

else {

System.out.println("Please enter a number in 1 to 26 range");

}

}

}

Question 6

Write a program to input two characters from the keyboard. Find the difference (d) between their ASCII codes. Display the following messages:

If d=0 : both the characters are same.

If d<0 : first character is smaller.

If d>0 : second character is smaller.

Sample Input :

D

P

Sample Output :

d= (68-80) = -12

First character is smaller

import java.util.Scanner;

public class ASCIIDiff

{

public static void main(String [] args) {

Scanner in = new Scanner(System.in);

System.out.print("Enter first character: ");

char ch1 = in.next().charAt(0);

System.out.print("Enter second character: ");

char ch2 = in.next().charAt(0);

int d = (int)ch1 - (int)ch2;

if (d > 0)

System.out.println("Second character is smaller");

else if (d < 0)

System.out.println("First character is smaller");

else

System.out.println("Both the characters are same");

}

}

Question 7

Write a program to input a set of any 10 integer numbers. Find the sum and product of the numbers. Join the sum and product to form a single number. Display the concatenated number.

[Hint: let sum=245 and product = 1346 then the number after joining sum and product will be 2451346]

import java.util.Scanner;

public class ProdConcat

{

public static void main(String [] args){

Scanner in = new Scanner(System.in);

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

long sum = 0, prod = 1;

for (int i = 0; i < 10; i++) {

int n = in.nextInt();

sum += n;

prod *= n;

}

String s = Long.toString(sum) + Long.toString(prod);

long r = Long.parseLong(s);

System.out.println("Concatenated Number = " + r);

}

}

Question 8

Write a menu driven program to generate the upper case letters from Z to A and lower case letters from 'a' to 'z' as per the user's choice.

Enter '1' to display upper case letters from Z to A and Enter '2' to display lower case letters from a to z.

import java.util.Scanner;

public class Letters

{

public static void main(String [] args) {

Scanner in = new Scanner(System.in);

System.out.println("Enter '1' to display upper case letters from Z to A");

System.out.println("Enter '2' to display lower case letters from a to z");

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

int ch = in.nextInt();

int count = 0;

switch (ch) {

case 1:

for (int i = 90; i > 64; i--) {

char c = (char)i;

System.out.print(c);

System.out.print(" ");

count++;

//Print 10 characters per line

if (count == 10) {

System.out.println();

count = 0;

}

}

break;

case 2:

for (int i = 97; i < 123; i++) {

char c = (char)i;

System.out.print(c);

System.out.print(" ");

count++;

//Print 10 characters per line

if (count == 10) {

System.out.println();

count = 0;

}

}

break;

default:

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

}

}

}

Question 9

Write a program to input a letter. Find its ASCII code. Reverse the ASCII code and display the equivalent character.

Sample Input: Y

Sample Output: ASCII Code = 89

Reverse the code = 98

Equivalent character: b

import java.util.Scanner;

public class ASCIIReverse

{

public static void main() {

Scanner in = new Scanner(System.in);

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

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

int a = (int)l;

System.out.println("ASCII Code = " + a);

int r = 0;

while (a > 0) {

int digit = a % 10;

r = r * 10 + digit;

a /= 10;

}

System.out.println("Reversed Code = " + r);

System.out.println("Equivalent character = " + (char)r);

}

}

Question 10

Write a menu driven program to display

(i) first five upper case letters

(ii) last five lower case letters as per the user's choice.

Enter '1' to display upper case letters and enter '2' to display lower case letters.

import java.util.Scanner;

public class MenuUpLowCase

{

public static void main(String [] args) {

Scanner in = new Scanner(System.in);

System.out.println("Enter '1' to display upper case letters");

System.out.println("Enter '2' to display lower case letters");

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

int ch = in.nextInt();

switch (ch) {

case 1:

for (int i = 65; i <= 69; i++)

System.out.println((char)i);

break;

case 2:

for (int i = 118; i <= 122; i++)

System.out.println((char)i);

break;

default:

break;

}

}

}

Question 11

Write a program in Java to display the following patterns:

(i)

A

ab

ABC

abcd

ABCDE

public class Pattern

{

public void displayPattern() {

for (int i = 65; i < 70; i++) {

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

if (i % 2 == 0)

System.out.print((char)(j+32));

else

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

}

System.out.println();

}

}

}

(ii)

ZYXWU

ZYXW

ZYX

ZY

Z

public class Pattern

{

public void displayPattern() {

for (int i = 86; i <= 90; i++) {

for (int j = 90; j >= i; j--) {

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

}

System.out.println();

}

}

}

(iii)

ABCDE

ABC

A

public class KboatPattern

{

public void displayPattern() {

for (int i = 69; i >= 65; i = i - 2) {

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

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

}

System.out.println();

}

}

}

Output

(iv)

PRTV

PRT

PR

P

public class KboatPattern

{

public void displayPattern() {

for (int i = 86; i >= 80; i = i - 2) {

for (int j = 80; j <= i; j = j + 2) {

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

}

System.out.println();

}

}

}

(v)

A*B*C*D*E*

A*B*C*D*

A*B*C*

A*B*

A*

public class Pattern

{

public void displayPattern() {

for(int i = 69; i >= 65; i--) {

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

System.out.print((char)j + "*");

}

System.out.println();

}

}

}

(vi)

a a a a a

b b b b b

A A A A A

B B B B B

public class Pattern

{

public void displayPattern() {

int a = 97;

for (int i = 1; i <= 4; i++) {

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

System.out.print((char)a + " ");

}

a++;

if (i == 2)

a = 65;

System.out.println();

}

}

}