Example: Remove Vowels from String using Switch Case in C

// Remove Vowels from String using Switch Case
#include <stdio.h>  // Required for printf, gets (use fgets for safety)
#include <string.h> // Required for strlen
#include <ctype.h>  // Required for tolower

#define MAX_LENGTH 100

int main() {
    char str[MAX_LENGTH];
    char modifiedStr[MAX_LENGTH]; // Optional: to store in a new string
    int i, j = 0;

    // Step 1: Prompt user for input string
    printf("Enter a string: ");
    // Using fgets is safer than gets to prevent buffer overflows
    // Read up to MAX_LENGTH-1 characters, store in str, from stdin
    fgets(str, MAX_LENGTH, stdin);

    // Remove the trailing newline character that fgets might read
    str[strcspn(str, "\n")] = 0;

    // Step 2: Iterate through the original string
    for (i = 0; str[i] != '\0'; i++) {
        // Step 3: Convert current character to lowercase for case-insensitive check
        char currentChar = tolower(str[i]);

        // Step 4: Use switch case to check if the character is a vowel
        switch (currentChar) {
            case 'a':
            case 'e':
            case 'i':
            case 'o':
            case 'u':
                // It's a vowel, do not copy it. Skip to the next character.
                break;
            default:
                // It's a consonant or non-alphabetic character, copy it.
                modifiedStr[j] = str[i];
                j++; // Increment the write index
                break;
        }
    }

    // Step 5: Null-terminate the modified string
    modifiedStr[j] = '\0';

    // Step 6: Print the modified string
    printf("String after removing vowels: %s\n", modifiedStr);

    return 0;
}