Five Java Programs asked in interview from Freshers

1. Write a program (WAP) to reverse a number or string.

Source code:

import java.util.Scanner;

public class  ReString

{

public static void main(String[] args) 

{

Scanner sc = new Scanner(System.in);

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

String str = sc.nextLine();

String ReStr="";

for(int i=str.length()-1;i>=0;i--) {

ReStr = ReStr+str.charAt(i);

}

System.out.println("Reverse of String "+ str + " is " +ReStr);

}

}

For Beginners

To run:

Firstly Save it with any name or  by Class name

For example: ReString.java

To Go to the Local disk or drive where you saved the programs(Open Command prompt)

For example for E drive: e: 

Then press: enter

Now press cd folder name

Finally For Compilation : javac filename.java (as shown in image ''javac ReString.java'')

To execute: java classname (as shown in image 'java ReString'')

Output:

2. Write a program (WAP) to find factorial of any number.

Source code:

import java.util.Scanner;

class  Facto

{

public static void main(String[] args) 

{

int fact=1;

Scanner sc = new Scanner(System.in);

System.out.println("Enter Factorial:");

int n=sc.nextInt();

for(int i=n;i>0;i--) 

fact=fact*i;

System.out.println("Factorial of "+n+" is" + fact);

}

}

Output:

3. Write a program (WAP) to find a number is Palinedrome or not.

Source code:

import java.util.Scanner;

 

public class Palinedrome {

 

 

 public static void main(String[] args) {

 

  Scanner scanner = new Scanner(System.in);

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

 

  String str = scanner.nextLine();

  String reverseStr = "";

 

  for(int i = str.length() - 1; i >= 0; i--){

   reverseStr = reverseStr + str.charAt(i);

  }

 

  if(str.equals(reverseStr)){

   System.out.println("String is palindrome");

  } else {

   System.out.println("String is not palindrome");

  }

 }

}

Output:

3. Write a program (WAP) to find  fibonacci series.

Source code:

import java.util.Scanner;

 

public class FibonacciSeries {

 

 

 public static void main(String[] args) {

 

int prev=0, nxt=1,sum=0, noe;

  Scanner in = new Scanner(System.in);

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

 noe = in.nextInt();

 System.out.print(prev+"\t "+nxt);

  for(int i=0; i <=noe; i++){

   sum=prev+nxt;

   prev=nxt;

   nxt=sum;

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

  } 

 }

}

Output:

Note: As it takes prev and nxt as addition that's why number of elements is 12 here.

5. Write a program (WAP) for Swapping.

Source code:

import java.util.Scanner;

class  Swapping

{

public static void main(String[] args) 

{

Scanner sr = new Scanner(System.in);

System.out.println("Enter first number:");

int a=sr.nextInt();

                                  System.out.println("Enter second number:");

int b=sr.nextInt();

System.out.println("Initial value of a:"+a+"and b:"+b);

a=a+b;

b=a-b;

a=a-b;

System.out.println("After Swapping value of a:"+a+"and b:"+b);

}

}

Output: