Example: CharacterFrequencyUsingNestedLoops in Java

// CharacterFrequencyUsingNestedLoops
public class Main {
    public static void main(String[] args) {
        String inputString = "programming";
        
        // Step 1: Convert string to a character array to allow marking
        char[] stringChars = inputString.toCharArray();
        int n = stringChars.length;
        
        System.out.println("Character frequencies (using nested loops):");

        // Step 2: Outer loop to iterate through each character
        for (int i = 0; i < n; i++) {
            // Skip character if it has already been counted (marked as 0)
            if (stringChars[i] == 0) { 
                continue;
            }

            int count = 1; // Current character counts itself

            // Step 3: Inner loop to compare with subsequent characters
            for (int j = i + 1; j < n; j++) {
                if (stringChars[i] == stringChars[j]) {
                    count++;
                    // Step 4: Mark the duplicate character to avoid recounting
                    stringChars[j] = 0; 
                }
            }
            // Step 5: Print frequency if character was not marked
            System.out.println(stringChars[i] + ": " + count);
        }
    }
}