Code - Blocks I

Simple Programs PART-1 :

Easy understandable codes are without sample input & output, so please understand the basic logic's and work it out. some codes are given with sample input and output. Next-level to basic programs are available in

PART-II module.

1) Java Program to Check if a Given Integer is Positive or Negative.

import java.util.*;

public class Hello

    public static void main(String[] args)

        int n;

        Scanner s = new Scanner(System.in);

        System.out.print("Enter the number you want to check:");

        n = s.nextInt();

        if(n > 0)

            System.out.println("Positive");

        else if(n < 0)

            System.out.println("Negative");

        else

            System.out.println("neither Positive nor Negative ");

2) Java Program to Check if a Given Integer is Odd or Even.

import java.util.*;

public class Hello

    public static void main(String[] args)

        int n;

        Scanner s = new Scanner(System.in);

        System.out.print("Enter the number you want to check:");

        n = s.nextInt();

        if(n % 2 == 0)

            System.out.println("Even ");

        else

            System.out.println("Odd ");

3) Java Program to Find the Biggest of 3 Numbers.

import java.util.*;

public class Hello

    public static void main(String[] args)

        int x, y, z;

        Scanner s = new Scanner(System.in);

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

        x = s.nextInt();

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

        y = s.nextInt();

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

        z = s.nextInt();

        if(x > y && x > z)

            System.out.println("Largest number is:"+x);

        else if(y > z)

            System.out.println("Largest number is:"+y);

        else

            System.out.println("Largest number is:"+z);

4) Java Program to Calculate the Sum of Odd & Even Numbers.

import java.util.*;

public class Hello

    public static void main(String[] args)

        int n, sumEven = 0, sumOdd = 0;

        Scanner s = new Scanner(System.in);

        System.out.print("Enter the number of elements in array:");

        n = s.nextInt();

        int[] a = new int[n];          //to declare an array

        System.out.println("Enter the elements of the array:");

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

            a[i] = s.nextInt();

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

            if(a[i] % 2 == 0)

                sumEven = sumEven + a[i];

            else

                sumOdd = sumOdd + a[i];

        System.out.println("Sum of Even Numbers:"+sumEven);

        System.out.println("Sum of Odd Numbers:"+sumOdd);

5) Java Program to Read Two Integers M and N & Swap their Values.

import java.util.*;

public class Swap_Integers

    public static void main(String args[])

        int m, n, temp;

        Scanner s = new Scanner(System.in);

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

        m = s.nextInt();

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

        n = s.nextInt();

        temp = m;

        m = n;

        n = temp;

        System.out.println("After Swapping");

        System.out.println("First number:"+m);

        System.out.println("Second number:"+n);

6) Java Program to Reverse a Given Number.

import java.util.*;

public class Reverse_Number

    public static void main(String args[])

        int m, n, sum = 0;

        Scanner s = new Scanner(System.in);

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

        m = s.nextInt();

        System.out.println("Reverse of the number is:");

        while(m != 0)

            n = m % 10;

            System.out.println(n);

            m = m / 10;

7) Java Program to Accept two Integers and Check if they are Equal.

import java.util.*;

public class Equal_Integer

    public static void main(String[] args)

        int m, n;

        Scanner s = new Scanner(System.in);

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

        m = s.nextInt();

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

        n = s.nextInt();

        if(m == n)

            System.out.println(m+" and "+n+" are equal ");

        else

           System.out.println(m+" and "+n+" are not equal ");

8)  Java Program to Compute the Sum of Digits in a given Integer.

import java.util.*;

public class Digit_Sum

    public static void main(String args[])

        int m, n, sum = 0;

        Scanner s = new Scanner(System.in);

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

        m = s.nextInt();

        while(m > 0)

            n = m % 10;

            sum = sum + n;

            m = m / 10;

        System.out.println("Sum of Digits:"+sum);

9) Java Program to Extract Digits at that position from a Given Integer

import java.util.*;

public class Extract_Digits

    public static void main(String args[])

        int n, m, a, i = 1, counter = 0;

        Scanner s=new Scanner(System.in);

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

        n = s.nextInt();

        m = n;

        while(n > 0)

        {            n = n / 10;

            counter++;

        while(m > 0)

            a = m % 10;

             System.out.println("Digits at position "+counter+":"+a);

            m = m / 10;

            counter--;

10 )  Java Program to Print Binary Equivalent of an Integer using Recursion.

import java.util.*;

public class Binary_Recursion

    public static void main(String[] args)

        int n;

        Scanner s = new Scanner(System.in);

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

        n = s.nextInt();

        Binary_Recursion obj = new Binary_Recursion();

        String m = obj.Binary(n);

        System.out.println("Answer:"+m);

    String Binary(int x)

        if(x > 0)

            int a = x % 2;

            x = x / 2;

            return a + "" + Binary(x);

        return "";

Sample input:

Enter the number:19

Sample output:

Answer:11001

11) Java Program to Increment by 1 All the Digits of a given Integer

import java.util.*;

public class Increment_Digits

   public static void main(String[] args)

        int n, m = 0, a;

        Scanner s = new Scanner(System.in);

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

        n = s.nextInt();

        while(n > 0)

            a = n % 10;

            a++;

            m = m * 10 + a;

            n = n / 10;

        n = m;

        m = 0;

        while(n > 0)

            a = n % 10;

            m = m * 10 + a;

            n = n / 10;

        System.out.println("Result:"+m);

Sample input:

Enter any number:4567

Sample output:

Result:5678

12) Java Program to Convert Integer Values into Binary.

import java.util.*;

public class Decimal_Binary

{    public static void main(String[] args)

        int n, m;

        String x = "";

        Scanner s = new Scanner(System.in);

        System.out.print("Enter the Decimal Number:");

        n = s.nextInt();

        while(n > 0)

            int a = n % 2;

            x = a + x;

            n = n / 2;

        System.out.println(x);

Sample input:

Enter the Decimal Number:19

Sample Output:

13) Java Program to Convert a Given Number of Days in terms of Years, Weeks & Days.

import java.util.*;

public class Year_Week_Day

    public static void main(String args[])

        int m, year, week, day;

        Scanner s = new Scanner(System.in);

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

        m = s.nextInt();

        year = m / 365;

        m = m % 365;

        System.out.println("No. of years:"+year);

        week = m / 7;

        m = m % 7;

        System.out.println("No. of weeks:"+week);

        day = m;

        System.out.println("No. of days:"+day);

Sample input:

Enter the number of days:756

Sample output:

No. of years:2

No. of weeks:3

No. of days:5

14) Java Program to Convert Integer Values into Byte, Character, Float.

import java.util.*;

public class Integer_Conversion

   public static void main(String[] args)

        int a;

        byte b;

        char c;

        float d;

        Scanner s = new Scanner(System.in);

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

        a = s.nextInt();

        b = (byte) a;

        System.out.println("Conversion into byte:"+b);

        c = (char) a;

        System.out.println("Conversion into char:"+c);

        d = a;

        System.out.println("Conversion into float:"+d);

15) Java Program to Check if a Given Character is Vowel or Consonant using buffer reader function

import java.io.*;

import java.util.*;

public class Vowel_Consonant

    public static void main(String[] args)

        char n;

   BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));

        System.out.print("Enter the character you want to check:");

        n = (char) bf.read();

        n=n.toLowerCase();

        if(n=='a'||n=='e'||n=='i'||n=='o'||n=='u')

            System.out.print("Vowel");

        else

            System.out.ptint("Consonant");

16) Java Program to Check if given Alphabets are Uppercase or Lowercase or Digits.

import java.io.*;

public class Alphabet_Check

    public static void main(String args[])

        char m;

    BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));

        System.out.print("Enter any alphabet:");

        m = (char) bf.read();

        if(m >= 97 && m <= 123)

            System.out.println("Lower Case");

        else if(m >= 65 && m <= 96)

            System.out.println("Upper Case");

        else if(m >= 48 && m <= 57)

            System.out.println("Digit");

17) Java Program to Find Largest Between Three Numbers Using Ternary Operator.

import java.util.*;

public class Largest_Ternary

    public static void main(String[] args)

        int a, b, c, d;

        Scanner s = new Scanner(System.in);

        System.out.println("Enter all three numbers:");

        a = s.nextInt();

        b = s.nextInt();

        c = s.nextInt();

        d = c > (a > b ? a : b) ? c : ((a > b) ? a : b);

        System.out.println("Largest Number:"+d);

18) Java Program to Display Numbers from 1 to 10 Using For Loop.

import java.util.*;

public class Use_For_Loop

    public static void main(String[] args)

        for(int i = 1; i <= 10; i++)

            System.out.println(i);

19) Java Program to Check Whether Given Number is Divisible by 5.

import java.util.*;

public class Check_Divisiblity

    public static void main(String[] args)

        int n;

        Scanner s = new Scanner(System.in);

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

        n = s.nextInt();

        if(n % 5 == 0)

            System.out.println(n+" is divisible by 5");

        else

            System.out.println(n+" is not divisible by 5");

20 ) Java Program to Print Multiplication Table for any Number.

import java.util.*;

public class Multiplication_Table

    public static void main(String[] args)

        Scanner s = new Scanner(System.in);

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

  int n=s.nextInt();

        for(int i=1; i <= 10; i++)

            System.out.println(n+" * "+i+" = "+n*i);

Sample Input/output:

Enter number:7

7 * 1 = 7

7 * 2 = 14

7 * 3 = 21

7 * 4 = 28

7 * 5 = 35

7 * 6 = 42

7 * 7 = 49

7 * 8 = 56

7 * 9 = 63

7 * 10 = 70

21) Java Program to Reverse a Number and find the Sum of its Digits Using do-while Loop.

import java.util.*;

public class Use_Do_While

    public static void main(String[] args)

        int n, a, m = 0, sum = 0;

        Scanner s = new Scanner(System.in);

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

        n = s.nextInt();

do

            a = n % 10;

            m = m * 10 + a;

            sum = sum + a;

            n = n / 10;

        while( n > 0);

        System.out.println("Reverse:"+m);

        System.out.println("Sum of digits:"+sum);

22) java program to print without main function.

import java.util.*;

public class Without_Main

    static

         System.out.println("Hello World!!");

         System.exit(0);

    /*Does not work with JDK7*/

Sample output:

Hello World!!

23) java program to return value using a method.

import java.util.*;

public class Return_Value

    void input()

        int x, y, z;

        Scanner s = new Scanner(System.in);

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

        x = s.nextInt();

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

        y = s.nextInt();

        z = add(x, y);

        System.out.println("Result:"+z);

    int add(int a, int b)

        int c;

        c = a + b;

        return c;

    public static void main(String[] args)

        Return_Value obj = new Return_Value();

        obj.input();

sample Input:

Enter first integer:5

Enter second integer:6

sample output:

Result:11

24) java code to find the byte sum of two integer values.

import java.util.*;

public class Byte_Sum

    public static void main(String[] args)

        byte a, b;

        int x, y, z;

        Scanner s = new Scanner(System.in);

        System.out.print("Enter first byte value:");

        a = s.nextByte();

        x = a;

        System.out.print("Enter second byte value:");

        b = s.nextByte();

        y = b;

        z = x + y;

        System.out.println("Result:"+z);

Sample input:

Enter first byte value:124

Enter second byte value:115

Sample output:

Result:239

25) java program to print the statement without using semi-colon at the end.

import java.util.*;

public class Print_Without_Semicolon

     public static void main(String[] args)

        int i = 0;

        if(System.out.printf("Hi people!! ") == null) {}

        for(i = 1; i < 2; System.out.println("the text is Hello World."))

            i++;

Sample output:

Hi people!! the text is Hello World.

25) Java Program to Compute GCD.

import static java.lang.StrictMath.min;

import java.util.*;

public class GCD

    public static void main(String args[])

        int a, b, GCD = 1;

        Scanner s = new Scanner(System.in);

        System.out.print("Enter First Number:");

        a = s.nextInt();

        System.out.print("Enter Second Number:");

        b = s.nextInt();

        int n = min(a,b);

        for(int i = 2; i < n; i++)

            while(a % i == 0 && b % i==0)

                GCD = GCD * i;

                a = a / i;

                b = b / i;

        System.out.println("Greatest Common Divisor:"+GCD);

Sample input:

Enter First Number:24

Enter Second Number:16

Sample output:

Greatest Common Divisor:8

26) java program to print sum of n natural numbers

import java.util.*;

public class Natural

    public static void main(String args[])

        int x, i = 1 ;

        int sum = 0;

        System.out.println("Enter Number of items :");

        Scanner s = new Scanner(System.in);

        x = s.nextInt();

        while(i <= x)

            sum = sum +i;

            i++;

        System.out.println("Sum of "+x+" numbers is :"+sum);

sample input:

Enter Number of items :

Sample output:

Sum of 55 numbers is :1540

27) java program to print the perfect squares between 1 to n

class CountSquares {

static int countSquares(int a, int b)

int cnt = 0;

for (int i = a; i <= b;

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

if (j * j == i)

                    cnt++;

return cnt;

public class PerfectSquares {

public static void main(String[] args)

int a = 1, b = 25;

CountSquares obj = new CountSquares();

System.out.print("Count of squares is " + obj.countSquares(a, b));

Head count of birds and animals

import java.util.*;

public class Main {

    public static void main(String[] args)

  Scanner sc=new Scanner(System.in);

  int heads=sc.nextInt();

  int legs=sc.nextInt();

  int birds=0;

  for(birds=0;birds<=heads;birds++)

      if(birds*2+(heads-birds)*4==legs)

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

          System.out.print(heads-birds);

input 1:

27 84

output 1:

12 15

Interlace between even and odd integers:

import java.util.*;

public class MyClass

    public static void main(String args[])

        Scanner sc=new Scanner(System.in);

        int num1=sc.nextInt();

        int num2=sc.nextInt();

        for(int index1=num1,index2=num2;index1<=num2;index1++,index2--)

            if(index1%2==1)

               System.out.print(index1+" ");

            if(index2%2==0)

               System.out.print(index2+" ");

input 1:

output 1:

5 10 7 8 9 6 11

Print days in a Month:

import java.util.*;

public class Main

    public static void main(String[] args)

Scanner sc=new Scanner(System.in);

int n=sc.nextInt();

if(n>=13)

System.out.print("Invalid");

else if(n==1)

System.out.print("31");

else if(n==2)

System.out.print("28");

else if(n==3)

System.out.print("31");

else if(n==4)

System.out.print("30");

else if(n==5)

System.out.print("31");

else if(n==6)

System.out.print("30");

else if(n==7)

System.out.print("31");

else if(n==8)

System.out.print("31");

else if(n==9)

System.out.print("30");

else if(n==10)

System.out.print("31");

else if(n==11)

System.out.print("30");

else if(n==12)

System.out.print("31");

input 1:

output 1:

input 2:

output 2:

Invalid

Print the sum of ASCII values:

import java.util.*;

public class Hello

    public static void main(String[] args)

   Scanner sc=new Scanner(System.in);

  String str=sc.next();

  int l=str.length();

  int sum=0;

  for(int index=0;index<l;index++)

      sum+=(int)str.charAt(index);

  System.out.print(sum);

input 1:

abcde

output 1:

input 2:

abcd

output 2:

Print equivalent numerical values of characters of a string:

import java.util.*;

public class Main

    public static void main(String args[])

      Scanner sc=new Scanner(System.in);

      String str=sc.next();

      for(int index=0;index<str.length();index++)

          System.out.print(Character.getNumericValue(str.charAt(index))+" ");

input 1:

abcde

output 1:

10 11 12 13 14

input 2:

mnop

output 2:

22 23 24 25

Count number of flips to convert A to B:

import java.util.*;

public class Main

    public static void main(String[] args)

   Scanner sc=new Scanner(System.in);

  int a=sc.nextInt();

  int b=sc.nextInt();

  int num=a^b,count=0;

  while(num!=0)

      count+=num&1;

      num>>=1;

  System.out.print(count);

input 1:

10 20

output 1:

input 2:

12 10

output 2:

explanation:

binary representation of 12 is 1100 and 10 is 1010. hece two bits are to be flipped to convert A to B.

Number series Ap progression - find Nth term:

import java.util.Scanner;

public class Main

  public static void main(String[] args)

  Scanner sc=new Scanner(System.in);

  int a=sc.nextInt();

  int b=sc.nextInt();

  int c=sc.nextInt();

  int d=sc.nextInt();

  int k=sc.nextInt();

  int diff1=c-a;

  int diff2=d-b;

  int num1=a,num2=b;

  for(int index=1;index<=k-2;index++)

      if(index%2==1)

          num1=num1+diff1;

      else

          num2=num2+diff2;

  if(k%2==0)

  System.out.print(num2);

  else

  System.out.print(num1);

input 1:

1 1 5 4

output 1:

input 2:

2 1 4 7

output 2:

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