Simple Programs

Here you can find all type of String Operation programs (if i miss any please send me in Here)

Program: 1 Reverse a string with out using string lib functions.

public class HelloWorld{
     public static void main(String []args){
        String str = "BREJESH";
        int l=str.length();
        char[] ch=str.toCharArray();
        char t='\0';
        System.out.println("Original String is: "+str);
        for(int i=0;i<(str.length()/2);i++){
            t=ch[l-1];
            ch[l-1]=ch[i];
            ch[i]=t;
            l--;
        }
        System.out.println("Reverse String is: "+String.valueOf(ch));
     }
}

Output:

Original String is: BREJESH
Reverse String is: HSEJERB

Program: 2 Arrange String characters in alphabet order.

public class HelloWorld{
     public static void main(String []args){
        String str = "BREJESH";
        int l=str.length();
        char[] ch=str.toCharArray();        char t='\0';
        System.out.println("Original String is: "+str);
        for(int i=0;i<str.length();i++){
            for(int j=i;j<str.length();j++){
                if(ch[i] > ch[j]){
                    t=ch[i];
                    ch[i]=ch[j];
                    ch[j]=t;
                }   
            }
        }
        System.out.println("Alphabet Order String is: "+String.valueOf(ch));
     }
}

Output:

Original String is: BREJESH
Alphabet Order String is: BEEHJRS

Program: 3 Find Duplicate characters in given string

public class HelloWorld{
     public static void main(String []args){
        String str = "BREJESH";
        str = str.toLowerCase();
        int l=str.length();
        char[] ch=str.toCharArray();        int[] dup=new int[26];
        char t='\0';
        System.out.println("Original String is: "+str);
        for(int i=0;i<str.length();i++){
            if(dup[ch[i]-97] == -1){
                System.out.println("Duplicate found: " +ch[i]);
            }
            else
            dup[ch[i]-97]=-1;
        }
     }
}
 

Output:

Original String is: brejesh
Duplicate found: e

Program: 4 Print the characters count in the given string

public class HelloWorld{
     public static void main(String []args){
        String str = "BREJESH";
        str = str.toLowerCase();
        int l=str.length();
        char[] ch=str.toCharArray();        int[] dup=new int[26];
        char t='\0';
        System.out.println("Original String is: "+str);
        for(int i=0;i<str.length();i++){
            dup[ch[i]-97] = dup[ch[i]-97] + 1;
        }
        System.out.println("Char count: ");
        for(int i=0;i<26;i++){
            if(dup[i]!=0)            System.out.println((char)(i+97) + " - " + dup[i]);
        }
     }
}

Output:

Original String is: brejesh
Char count:
b - 1
e - 2
h - 1
j - 1
r - 1
s - 1

Program: 5 String Palindrome

public class HelloWorld{
     public static void main(String []args){
        String str = "BREJESH";
        int l=str.length(), f=0;
        char[] ch=str.toCharArray();
        System.out.println("Original String is: "+str);
        for(int i=0;i<(str.length()/2);i++){
            if(ch[i] != ch[l-1])
            f=1;
            l--;
        }
        if(f==1)
        System.out.println(str + " is not a palindrome");
        else
        System.out.println(str + " is a palindrome");
     }
}

Output:

Original String is: ABCBA
ABCBA is a palindrome

Program: Even Odd Number Example

public class FindEvenOrOddNumber {
       public static void main(String[] args) {
              int[] numbers = new int[]{1,2,3,4,5,6,7,8,9,10};
              for(int i=0; i < numbers.length; i++){
               if(numbers[i]%2 == 0)
                       System.out.println(numbers[i] + " is even number.");
                      else
                              System.out.println(numbers[i] + " is odd number.");
              }
        }
}

Output:

1 is odd number.
2 is even number.
3 is odd number.
4 is even number.
5 is odd number.
6 is even number.
7 is odd number.
8 is even number.
9 is odd number.
10 is even number.

Program: Find Largest and Smallest Number in given array

public class FindLargestSmallestNumber {
       public static void main(String[] args) {
              int numbers[] = new int[]{32,43,53,54,32,65,63,98,43,23};
              int smallest = numbers[0];
              int largetst = numbers[0];
              for(int i=1; i< numbers.length; i++){
               if(numbers[i] > largetst)
                       largetst = numbers[i];
                      else if (numbers[i] < smallest)
                              smallest = numbers[i];
              }
              System.out.println("Largest Number is : " + largetst);
              System.out.println("Smallest Number is : " + smallest);
        }
}

Output:

Largest Number is : 98
Smallest Number is : 23

Program: Factorial

public class NumberFactorial {
       public static void main(String[] args) {
              int number = 5;
              int factorial = number;
              for(int i =(number - 1); i > 1; i--){
               factorial = factorial * i;
              }
              System.out.println("Factorial of a number is " + factorial);
        }
}

Output:

Factorial of a number is 120

Program: Factorial Using Recursion

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class JavaFactorialUsingRecursion {
       public static void main(String args[]) throws NumberFormatException, IOException{
              System.out.println("Enter the number: ");
              BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
              int a = Integer.parseInt(br.readLine());
              int result= fact(a);
              System.out.println("Factorial of the number is: " + result);
       }
       static int fact(int b)
       {
        if(b <= 1)
         return 1;
               else
                return b * fact(b-1);
        }
}

Output:

Enter the number:
5
Factorial of the number is: 120

Program: Reverse Number

public class ReverseNumber {
       public static void main(String[] args) {
              int number = 1234;
              int reversedNumber = 0;
              int temp = 0;
              while(number > 0){
               temp = number%10;
                      reversedNumber = reversedNumber * 10 + temp;
                      number = number/10;
              }
              System.out.println("Reversed Number is: " + reversedNumber);
        }
}

Output:

Reversed Number is: 4321

Program: Swap Numbers

public class SwapElementsExample {
       public static void main(String[] args) {
              int num1 = 10;
              int num2 = 20;
              System.out.println("Before Swapping");
              System.out.println("Value of num1 is :" + num1);
              System.out.println("Value of num2 is :" +num2);
              swap(num1, num2);
       }
       private static void swap(int num1, int num2) {
               int temp = num1;
               num1 = num2;
               num2 = temp;
               System.out.println("After Swapping");
               System.out.println("Value of num1 is :" + num1);
               System.out.println("Value of num2 is :" +num2);
       }
}

Output:

Before Swapping
Value of num1 is :10
Value of num2 is :20
After Swapping
Value of num1 is :20
Value of num2 is :10

Program: Swap Numbers Without Using Third Variable

public class SwapElementsWithoutThirdVariableExample {
       public static void main(String[] args) {
              int num1 = 10;
              int num2 = 20;
              System.out.println("Before Swapping");
              System.out.println("Value of num1 is :" + num1);
              System.out.println("Value of num2 is :" +num2);
              num1 = num1 + num2;
              num2 = num1 - num2;
              num1 = num1 - num2;
              System.out.println("Before Swapping");
              System.out.println("Value of num1 is :" + num1);
              System.out.println("Value of num2 is :" +num2);
       } 
}

Output:

Before Swapping
Value of num1 is :10
Value of num2 is :20
Before Swapping
Value of num1 is :20
Value of num2 is :10