Program to reverse a string without using String API.

Explanation :
If str ="Hello world" then output will be "dlrow olleH".

Code:

public class Reverse
{
       public static void main(String[] args)
      {
           String str="Hello world";
           String rev="";
          for(int i=str.length()-1;i>=0;--i)
          {
            revs +=str.charAt(i);
           }

           System.out.println(rev);
}
}