By : Aymane BENDAHMANE July 12, 2023

Write a function that will break up camel casing, using a space between words.

Example

"camelCasing"  =>  "camel Casing"
"identifier"   =>  "identifier"
""             =>  ""

Approach 1 : Implementing a for loop

camelCase method:

• It uses a StringBuilder to build the camel case string.
• It iterates over each character of the input string and checks if the character is uppercase and not the first character.
• If the condition is true, it appends a space followed by the character to the StringBuilder, otherwise, it appends just the character.
• Finally, it returns the string representation of the StringBuilder.

public static String camelCase(String input) {
        
        StringBuilder stringBuilder = new StringBuilder();
        
        for (int i = 0; i < input.length(); i++) {

            char character = input.charAt(i);
            
            if (Character.isUpperCase(character) && i != 0)
                stringBuilder.append(" ");
            
            stringBuilder.append(input.charAt(i));
        }
        return stringBuilder.toString();
    }

unit testing :

@Test
    public void IsUpperCaseUsingForLoop() {
        assertEquals("Incorrect", "camel Casing",      camelCase("camelCasing"));
        assertEquals("Incorrect", "Damel Casing Cest", camelCase("DamelCasingCest"));
        assertEquals("Incorrect", "camelcasingtest",   camelCase("camelcasingtest"));
    }

As we can see, the test took 10 ms to finish

Approach 2 : Using streams

camelCase2 method:

• This method uses the Arrays.stream method to convert the input string into a stream of individual characters.