CODEWITHSUNDEEP
javastringmethodschar
user5316498
user5316498

Reputation:

Capitalizing the first letter in a string. What am I doing wrong?

What am I doing wrong? When I run my program it only prints some of my string, and it does not capitalize the first letter..

public class StringTraining extends ConsoleProgram {
    public void run() {
        String str = "halOOlOO";
        capitalize(str);
    }


    private String capitalize(String str){
        String s = "";
        char ch;
        for(int i = 0;i<str.length();i++) {
            ch = str.charAt(i);
            if(i==0 && Character.isLowerCase(ch)) {
                Character.toUpperCase(ch);
                s += ch;
                i++;
            } else {
                Character.toLowerCase(ch);
                s += ch;
                i++;
            }
        }
        println(s);
        return s;
    }

}

Upvotes: 1

Views: 101

Answers (5)

Srijani Ghosh
Srijani Ghosh

Reputation: 4216

Change your capitalize(String str) method like this -

 private static String capitalize(String str) {
    char[] chars = str.toCharArray();
    String caps = chars[0]+"";
    caps = caps.toUpperCase();
    String output = caps;
    for(int i=1;i<chars.length;i++) {
        output = output + chars[i];
    }
    return output;
}

Output :

HalOOlOO

Upvotes: 0

ccc
ccc

Reputation: 370

Remove some unnecessary codes from your capitalize(String) method such as i++ and use
s += String.valueOf(Character.toUpperCase(ch)); code instead of 

Character.toUpperCase(ch);
s += ch;

Complete capitalize(String) method

private static String capitalize(String str) {
    String s = "";
    char ch;
    for (int i = 0; i < str.length(); i++) {
        ch = str.charAt(i);
        if (i == 0 && Character.isLowerCase(ch)) {
            s += String.valueOf(Character.toUpperCase(ch));
        } else {
            s += String.valueOf(Character.toLowerCase(ch));
        }
    }
    println(s);
    return s;
}

Upvotes: 2

JJF
JJF

Reputation: 2777

You need to assign the variable ch to the upper or lower case value:

for(int i = 0;i<str.length();i++) {
        ch = str.charAt(i);
        if(i==0 && Character.isLowerCase(ch)) {
            ch = Character.toUpperCase(ch);
            s += ch;
        } else {
            ch = Character.toLowerCase(ch);
            s += ch;
        }
    }

Upvotes: 4

Ekinydre
Ekinydre

Reputation: 19

toLowerCase() return a string, you need to assign it to ch. You also need to increment your i only one time (in the for, and not in the if)

Upvotes: 1

Yassin Hajaj
Yassin Hajaj

Reputation: 21965

  1. You should not increment i again in the loop since it will be done automatically in the signature of the loop.

  2. You have to assign Character.toUpperCase(ch) to the String or append it.

  3. I'd suggest you use a StringBuilder when looping to build a String object

Correction

private static String capitalize(String str){
    StringBuilder s = new StringBuilder();
    char ch;
    for(int i = 0;i<str.length();i++) {
        ch = str.charAt(i);
        if(i==0 && Character.isLowerCase(ch)) {
            s.append(Character.toUpperCase(ch));
        } else {
            s.append(Character.toLowerCase(ch));
        }
    }
    return s.toString();
}

Output

Halooloo

Upvotes: 4

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