String Reverse in Java Program | For | Recursion | Function | StringBuilder | StringBuffer | Stream

String reverse in Java program using for loop, recursion, and function.

In this article, you will learn how to reverse in Java program using for loop, recursion, and function.

 

Example

 

You should have knowledge of the following topics in Java programming to understand this program:

• Java java.util.Scanner package
• Java main() method
• Java System.out.println() function
• Java for loop
• Java Recursion
• Java Function

 

Source Code

// String Reverse in Java using For loop
import java.util.Scanner;

public class Main {
    // It's the driver function
    public static void main(String[] args) {
    	Scanner in = new Scanner(System.in);
        System.out.println("Enter a string to make reverse::\n");
        String x=in.nextLine();

        // It will print the final output
        System.out.print ("The reverse of the string is:: ");
        for (int i=(x.length()-1); i>=0; i--) {
            System.out.print (x.charAt(i));
        }
        System.out.println("\n");
    }
}

Run

Output

 

Explanation

In this given program, we have taken input hello example from the user via the system console. Then we iterate over the given input from the right side to the left side to print the characters.

Then It will be returned the reversed string elpmaxe olleh the output of the given program.

 

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String Reverse in Java using Recursion

// String Reverse in Java using Recursion
import java.util.Scanner;

public class Main {
    // It recursive function will print the characters on the right side
    public static int revString(String x, int l) {
        if (l>=0) {
            System.out.print (x.charAt(l));
            l--;
            revString(x, l);
        }
        return 0;
    }
    
    // It's the driver function
    public static void main(String[] args) {
    	Scanner in = new Scanner(System.in);
        System.out.println("Enter a string to make reverse::\n");
        String x=in.nextLine();

        // It will print the final output
        System.out.print ("The reverse of the string is:: ");
        revString(x, x.length()-1);
        System.out.println("\n");
    }
}

Run

 

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String Reverse in Java using Function

// String Reverse in Java using Function
import java.util.Scanner;

public class Main {
    // It will reverse the input string
    public static void revString(String x) {
        for (int i=(x.length()-1); i>=0; i--) {
            System.out.print (x.charAt(i));
        }
    }
    
    // It's the driver function
    public static void main(String[] args) {
    	Scanner in = new Scanner(System.in);
        System.out.println("Enter a string to make reverse::\n");
        String x=in.nextLine();

        // It will print the final output
        System.out.print ("The reverse of the string is:: ");
        revString(x);
        System.out.println("\n");
    }
}

Run

 

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String Reverse in Java using Char Array

// String Reverse in Java using Char Array
import java.util.Scanner;

public class Main {
    // It's the driver function
    public static void main(String[] args) {
    	Scanner in = new Scanner(System.in);
        System.out.println("Enter a string to make reverse::\n");
        String x=in.nextLine();
        
        // it will create a character array of the same size as the input string
        int length=x.length();
        char[] CharStr=new char[length];

        // It will reverse the input string
        System.out.print ("The reverse of the string is:: ");
        for (int i=(length-1); i>=0; i--) {
            CharStr[length-i-1]=x.charAt(i);
        }
        
        //  It will print the final output
        System.out.println(String.copyValueOf(CharStr)+"\n");
    }
}

Run

Output

 

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String Reverse in Java using Method getBytes()

// String Reverse in Java using Method getBytes()
import java.util.Scanner;

public class Main {
    // It's the driver function
    public static void main(String[] args) {
    	Scanner in = new Scanner(System.in);
        System.out.println("Enter a string to make reverse::\n");
        String x=in.nextLine();
        
        // getBytes() method will convert the input string into bytes[]
        byte[] StrByteArray=x.getBytes();
        int length=StrByteArray.length;
        byte[] Result=new byte[length];

        // It will reverse the input string
        System.out.print ("The reverse of the string is:: ");
        for (int i=(length-1); i>=0; i--) {
            Result[length-i-1]=StrByteArray[i];
        }
        
        //  It will print the final output
        System.out.println((new String(Result))+"\n");
    }
}

Run

 

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String Reverse in Java using StringBuilder's Built-in Method reverse()

// String Reverse in Java using StringBuilder's Built-in Method reverse()
import java.util.Scanner;

public class Main {
    // It's the driver function
    public static void main(String[] args) {
    	Scanner in = new Scanner(System.in);
        System.out.println("Enter a string to make reverse::\n");
        String x=in.nextLine();
        
        // It will create the instance of the `StringBuilder` class
        StringBuilder SBinput=new StringBuilder();
        SBinput.append(x); // To append the value of x variable
        
        // It will reverse the input value
        SBinput.reverse();
        
        //  It will print the final output
        System.out.println("The reverse of the string is:: "+SBinput+"\n");
    }
}

Run

 

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String Reverse in Java using StringBuffer

// String Reverse in Java using StringBuffer
import java.util.Scanner;

public class Main {
    // It's the driver function
    public static void main(String[] args) {
    	Scanner in = new Scanner(System.in);
        System.out.println("Enter a string to make reverse::\n");
        String x=in.nextLine();
        
        // It will create the instance of the `StringBuffer` class
        StringBuffer SBuffInput=new StringBuffer(x);
        
        // It will reverse the input value
        SBuffInput.reverse();
        
        //  It will print the final output
        System.out.println("The reverse of the string is:: "+SBuffInput+"\n");
    }
}

Run

Output

 

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String Reverse in Java using Stream

// String Reverse in Java using Stream
import java.util.Scanner;
import java.util.stream.Collectors;
import java.util.stream.Stream;

public class Main {
    // It's the driver function
    public static void main(String[] args) {
    	Scanner in = new Scanner(System.in);
        System.out.println("Enter a string to make reverse::\n");
        String x=in.nextLine();
        
        // It will reverse the input string
        String reverseStr=Stream.of(x)
            .map(str -> new StringBuilder(str).reverse())
            .collect(Collectors.joining());
        
        //  It will print the final output
        System.out.println("The reverse of the string is:: "+reverseStr+"\n");
    }
}

Run

 

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String Reverse in Java using Method toCharArray()

// String Reverse in Java using Method toCharArray()
import java.util.Scanner;

public class Main {
    // It's the driver function
    public static void main(String[] args) {
    	Scanner in = new Scanner(System.in);
        System.out.println("Enter a string to make reverse::\n");
        String x=in.nextLine();
        
        // it will create a character array of the input string
        char[] charArr=x.toCharArray();
        int length=charArr.length;

        // It will reverse the input string
        System.out.print ("The reverse of the string is:: ");
        for (int i=(length-1); i>=0; i--) {
            System.out.print(charArr[i]);
        }
        System.out.println("\n");
    }
}

Run

Output

 

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String Reverse in Java using ArrayList Object | ListIterator

// String Reverse in Java using ArrayList Object | ListIterator
import java.util.*;
import java.util.Scanner;

public class Main {
    // It's the driver function
    public static void main(String[] args) {
    	Scanner in = new Scanner(System.in);
        System.out.println("Enter a string to make reverse::\n");
        String x=in.nextLine();
        
        // it will create a character array of the input string
        char[] charArr=x.toCharArray();
        List<Character> ArrList=new ArrayList<>();
        
        for (char c:charArr) {
            ArrList.add(c);
        }
        
        // It will reverse the input string
        System.out.print ("The reverse of the string is:: ");
        Collections.reverse(ArrList);
        ListIterator list = ArrList.listIterator();
        while (list.hasNext()) {
            System.out.print(list.next());
        }
        System.out.println("\n");
    }
}

Run