Answers for "reverse a string in java"

Reverse a string in java

// reverse a string using reverse() method of StringBuilder class
class ReverseUsingReverseMethod
{
   public static void main(String[] args)
   {
      String str = "Hello world Java";
      StringBuilder sb = new StringBuilder();
      // append string to StringBuilder
      sb.append(str);
      sb = sb.reverse();
      // printing reversed String
      System.out.println(sb);
   }
}

Reverse a string in java

// reverse a string using character array
class ReverseUsingCharacterArray
{
   public static void main(String[] args)
   {
      String str = "HelloWorldJava";
      char[] ch = str.toCharArray();
      for(int a = ch.length - 1; a >= 0; a--)
         System.out.print(ch[a]);
   }
}

reverse a string in java

Solution 1 

public static String StrReverse(String str) {

String reverse="";

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

reverse += str.toCharArray()[i];

 

return  reverse;

}

 

Solution 2 (using string buffer)

public  static String  Reverse(String str) {

return new StringBuffer(str).reverse().toString());

}

reverse a string in java

public class StringReverseExample{
   public static void main(String[] args) {
      String string = "abcdef";
      String reverse = new StringBuffer(string).reverse().toString();
      System.out.println("\nString before reverse: "+string);
      System.out.println("String after reverse: "+reverse);
   }
}

Reverse a string in java

// reverse a string using toCharArray() method
class ReverseUsingToCharArrayMethod
{
   public static void main(String[] args)
   {
      String str = "Hello World Java";
      char[] chTemp = str.toCharArray();
      int left, right = 0;
      right = chTemp.length - 1;
      for(left = 0; left < right ; left++, right--)
      {
         // swap values
         char temp = chTemp[left];
         chTemp[left] = chTemp[right];
         chTemp[right]=temp;
      }
      for(char c : chTemp)
         System.out.print(c);
      System.out.println();
   }
}

Reverse a string in java

// reverse a string using ByteArray
class ReverseStringByteArray
{
   public static void main(String[] args)
   {
      String input = "HelloWorld";
      // getBytes() method to convert string into bytes[].
      byte[] strByteArray = input.getBytes();
      byte[] output = new byte[strByteArray.length];
      // store output in reverse order
      for(int a = 0; a < strByteArray.length; a++)
         output[a] = strByteArray[strByteArray.length - a - 1];
      System.out.println(new String(output));
   }
}

reverse a string in java

// Not the best way i know but i wanted to challenge myself to do it this way so :)
public static String reverse(String str) {
  char[] oldCharArray = str.toCharArray();
  char[] newCharArray= new char[oldCharArray.length];
  int currentChar = oldCharArray.length-1;
  for (char c : oldCharArray) {
    newCharArray[currentChar] = c;
    currentChar--;
  }
  return new String(newCharArray);
}

reverse a string in java

public class Main {

    public static void main(String[] args) {
	// Write a Java program to reverse a string.
        Scanner input = new Scanner(System.in);
        System.out.println("Enter the String:");
        char[] letters = input.nextLine().toCharArray();
        System.out.println(" Reverse String");
        for(int i = letters.length -1; i >= 0; i--){
            System.out.print(letters[i]);
        }
    }
}

reverse a string in java

As we know that String is immutable. String class do not have reverse() method.