Java - Convert lower to upper case without using toUppercase()

Question

I'm trying to create a short program that would convert all letters that are uppercase to lowercase (from the command line input).

The following compiles but does not give me the result I am expecting. What would be the reason for this??

Eg) java toLowerCase BANaNa -> to give an output of banana

 public class toLowerCase{
        public static void main(String[] args){

            toLowerCase(args[0]);
        }

        public static void toLowerCase(String a){

            for (int i = 0; i< a.length(); i++){

                char aChar = a.charAt(i);
                if (65 <= aChar && aChar<=90){
                    aChar = (char)( (aChar + 32) ); 
                }

                System.out.print(a);
            }
         }   
    }

Answer 1

You are printing the String a, without modifying it. You can print char directly in the loop as follows:

public class toLowerCase
{
    public static void main(String[] args)
    {
        toLowerCase(args[0]);
    }

    public static void toLowerCase(String a)
    {
        for (int i = 0; i< a.length(); i++)
        {
            char aChar = a.charAt(i);
            if (65 <= aChar && aChar<=90)
            {
                aChar = (char)( (aChar + 32) ); 
            }
            System.out.print(aChar);
         }
     }
}    

Answer 2

Looks like homework to me, Just a hint. You are printing string a whereas you are modifying the char type aChar, its not modifying the original string a. (Remember strings are immutable).