Question

How to convert a character inside string to uppercase in Java

Answer 1

public class MyClass {
    public static String char_to_uppercase(String s, int idx) { 
        if (idx < 0 || idx > s.length()) return s;
         
        if (idx == s.length()) {
            s = s.substring(0, idx - 1) + s.substring(idx - 1, idx).toUpperCase();
        } else if (idx > 0) {
                   s = s.substring(0, idx - 1) + s.substring(idx - 1, idx).toUpperCase() + s.substring(idx);
               } else {
                        s = s.substring(idx, idx + 1).toUpperCase() + s.substring(idx + 1);
                 }
             
        return s;
    }
    public static void main(String args[]) {
        String s = "java programming"; 
 
        s = char_to_uppercase(s, 4);
        System.out.println(s); 
         
        s = char_to_uppercase(s, 0);
        System.out.println(s); 
         
        s = char_to_uppercase(s, s.length());
        System.out.println(s); 
    }
}
   
   
/*
run:
   
javA programming
JavA programming
JavA programminG
   
*/

 

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Answer 2

public class MyClass {
    public static String char_to_uppercase(String s, int idx) { 
        if (idx > 0) idx--;
        if (idx < 0 || idx > s.length()) return s;
         
        String tmp = "";
        for (int i = 0; i < s.length(); i++) {
            if (i == idx) {
                char ch = s.charAt(i);
                tmp += Character.toUpperCase(ch);
            }
            else
                tmp += s.charAt(i); 
        }
             
        return tmp;
    }
    public static void main(String args[]) {
        String s = "java programming"; 
 
        s = char_to_uppercase(s, 4);
        System.out.println(s); 
         
        s = char_to_uppercase(s, 0);
        System.out.println(s); 
         
        s = char_to_uppercase(s, s.length());
        System.out.println(s); 
    }
}
   
 
 
/*
run:
   
javA programming
JavA programming
JavA programminG
   
*/

 

70+ SQL courses for beginners and professionals

Answer 3

public class MyClass {
    public static String char_to_uppercase(String s, int idx) { 
        if (idx < 0 || idx > s.length()) return s;
         
        String tmp = "";
        for (int i = 0; i < s.length(); i++) {
            if (i == idx) {
                char ch = s.charAt(i);
                tmp += Character.toUpperCase(ch);
            }
            else
                tmp += s.charAt(i); 
        }
             
        return tmp;
    }
    public static void main(String args[]) {
        String s = "java programming"; 
 
        s = char_to_uppercase(s, 3);
        System.out.println(s); 
         
        s = char_to_uppercase(s, 0);
        System.out.println(s); 
         
        s = char_to_uppercase(s, s.length() - 1);
        System.out.println(s); 
    }
}
   
 
 
/*
run:
   
javA programming
JavA programming
JavA programminG
   
*/

 

70+ SQL courses for beginners and professionals

Answer 4

public class MyClass {
    public static String char_to_uppercase(String s, int idx) { 
        if (idx > 0) idx++;
        if (idx < 0 || idx > s.length()) return s;
         
        if (idx == s.length()) {
            s = s.substring(0, idx - 1) + s.substring(idx - 1, idx).toUpperCase();
        } else if (idx > 0) {
                   s = s.substring(0, idx - 1) + s.substring(idx - 1, idx).toUpperCase() + s.substring(idx);
               } else {
                        s = s.substring(idx, idx + 1).toUpperCase() + s.substring(idx + 1);
                 }
             
        return s;
    }
    public static void main(String args[]) {
        String s = "java programming"; 
 
        s = char_to_uppercase(s, 3);
        System.out.println(s); 
         
        s = char_to_uppercase(s, 0);
        System.out.println(s); 
         
        s = char_to_uppercase(s, s.length() - 1);
        System.out.println(s); 
    }
}
   
   
/*
run:
   
javA programming
JavA programming
JavA programminG
   
*/

 

70+ SQL courses for beginners and professionals