Reverse string method

Question

I am trying to solve the following problem but how do write the method that accepts String as an argument?

Write a method named printReverse

Answer 1

Something like this:

public class StringUtils {
    public static String reverse(String forward) {
        String result = "";
        // Put your code here
        return result;
    }
}

Answer 2

I highly recommend you to go through a basic tutorial.

You can simply do:

private static String myReverse(String str) {
    String reverse = "";
    int length = str.length();
    for( int i = length - 1 ; i >= 0 ; i-- ) {
       reverse = reverse + str.charAt(i);
    }
    return reverse;
}

And in your main, you simply:

String reversed = myReverse(in.nextLine());

Note that the method is static because you're referring to it from a static manner (main method). If you don't want it to be static, you'll have to access it via an object.

Also note that it's a good practice to always have curly brackets for for loops, even if it contains a single line.

Answer 3

private static void printReverse (String org)
{

  StringBuffer buffer = new StringBuffer(org);
  String reversedStr = buffer.reverse().toString();
  System.out.println("The reverse of the string \""
            + str + "\" is \"" + reversedStr + "\".");

}

in the main call the function

printReverse(original);

Answer 4

public class Dowhile {
  package dowhile;
  public static void main(String[] args) {
     // TODO code application logic here
     String message="i love java programming";
     int msglength = message.length();

     int index=msglength-1;
     while(index>=0)
     {
        System.out.print(message.charAt(index));
        index--;
     }  
  }
}

Answer 5

how do write the method that accepts String as an argument?

public static String reverse(String forward) {
   char[] strChar = forward.toCharArray();
   String reverse = "";

   for( int i = strChar.length - 1 ; i >= 0 ; i-- ) 
       reverse = reverse + strChar[i];

   return reverse;
}

But for large string appending character with + operator can be inefficient. And reversing string with above approach will result in wrong for uni-code mismatches. As it reverse the code units but not character. There is actually a built-in support available to reverse a string using StringBuilder which works correctly:

public static String reverse(String forward) {
   StringBuilder builder = new StringBuilder(forward);
   String reverse = builder.reverse().toString();
   return reverse;    
}

Answer 6

try this:

private static String reverseString(String str)
{
    String revString = "";

    for(int i=str.length()-1;i>=0;i--)
    {
        revString = revString + str.charAt(i);
    }
    return revString;
}