Why the program output is not displaying each string separately after getting UpperCased?

Question

the program is written for converting every first letter of the word to UpperCase

public class MainClass {

    public static void main(String[] args) {

        int i;
        String toBeCapped="";

        String str[] ={"This is a ball","This is a bat","this is the wicket"};
        int e=str.length;

        for(int j=0;j<e;j++)
        {
             String[] tokens = str[j].split("\\s");

             for( i = 0; i < tokens.length; i++)
             {
                 char capLetter = Character.toUpperCase(tokens[i].charAt(0));

                 toBeCapped +=  " " + capLetter + tokens[i].substring(1);
            }
            System.out.println(toBeCapped);
        }
    }
}

The output produced is as:-

This Is The Ball
This Is The Ball This Is The Bat
This Is The Ball This Is The Bat This Is The Wicket

I wanted the output to be as:-

This Is The Ball
This Is The 
This Is The Wicket

Please tell me what is the mistake I'm making. Thank You

You defined `toBeCapped` at the wrong scope. Move it three lines down, into the body of the outer `for` loop. — Marko Topolnik, Oct 10 '16 at 20:51

score 3 · Answer 1 · edited May 23 '17 at 12:00

3

The problem is that you never reset toBecapped to "" in the loop after printing.

Adding toBeCapped="" at the end of the loop after printing will fix this problem:

System.out.println(toBeCapped);
toBeCapped=""; // <<== Add this line

Note that string concatenation is relatively expensive in Java. A better approach is to use StringBuilder. See this Q&A for an in-depth discussion of this topic.

edited May 23 '17 at 12:00

Community

1
1

answered Oct 10 '16 at 20:48

Sergey Kalinichenko

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Also a good idea to use a [`StringBuffer`](https://docs.oracle.com/javase/7/docs/api/java/lang/StringBuffer.html) if you are concatenating Strings. – doublesharp Oct 10 '16 at 20:50
`StringBuffer` is always a good idea to concatenate `Strings` as it gives less time complexity than the normal `String Concatenation.` – Sanket Makani Oct 10 '16 at 21:02
Thank You bro.Also I would like to ask you that how I can create this program using StringBuffer? – Aradhya Jain Oct 10 '16 at 21:47

score 0 · Answer 2 · answered Oct 10 '16 at 20:50

Below is the problematic code. The += appends the characters to an already built toBeCapped String. You need to set the toBeCapped String to an empty one after the innermost for loop

for( i = 0; i < tokens.length; i++)
{
  char capLetter = Character.toUpperCase(tokens[i].charAt(0));

  toBeCapped +=  " " + capLetter + tokens[i].substring(1);
}
System.out.println(toBeCapped);
}
toBeCapped = "";

score 0 · Answer 3 · answered Oct 10 '16 at 20:55

Your code has a problem because toBeCapped variable is never reset after being used in the loop. A good coding practice is to declare and use loop variables inside the loop (not outside of it)

public static void main(String[] args) {
  String str[] ={"This is a ball","This is a bat","this is the wicket"};
  int e = str.length;

  for(int j=0;j<e;j++) {
    String toBeCapped="";
    String[] tokens = str[j].split("\\s");

    for(int i = 0; i < tokens.length; i++) {
      char capLetter = Character.toUpperCase(tokens[i].charAt(0));
      toBeCapped +=  " " + capLetter + tokens[i].substring(1);
    }
    System.out.println(toBeCapped);
  }
}

Why the program output is not displaying each string separately after getting UpperCased?

3 Answers3