The Count Vowels and Consonants program in C is designed to count and display the number of vowels and consonants in a given string. This program typically involves iterating through each character of the string, checking whether it's a vowel or a consonant, and maintaining a count of each.

Implementation of Count Vowels and Consonants Program

Here’s a simple implementation of this program in C:

#include <stdio.h>
#include <ctype.h>

int main() {
    char str[100];  // Array to hold the input string
    int vowels = 0; // Counter for vowels
    int consonants = 0; // Counter for consonants
    int i = 0; // Loop counter

    // Ask user for input
    printf("Enter a string: ");
    fgets(str, sizeof(str), stdin); // Read the input string including spaces

    // Iterate through each character in the string
    while (str[i] != '\0') {
        // Convert character to lowercase for uniform comparison
        char ch = tolower(str[i]);

        // Check if the character is a letter
        if (isalpha(ch)) {
            // Check if the character is a vowel
            if (ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u') {
                vowels++; // Increment vowel count
            } else {
                consonants++; // Increment consonant count
            }
        }
        i++; // Move to the next character
    }

    // Display the results
    printf("Vowels: %d\n", vowels);
    printf("Consonants: %d\n", consonants);

    return 0;
}

Explanation of the Program

1. Header Files:

   • #include <stdio.h>: For standard input and output functions.
   • #include <ctype.h>: For character handling functions like tolower() and isalpha().

2. Variable Declarations:

   • char str[100]: An array to hold the input string with a maximum length of 99 characters (the last character is reserved for the null terminator).
   • int vowels = 0: Counter for vowels, initialized to 0.
   • int consonants = 0: Counter for consonants, initialized to 0.
   • int i = 0: Loop counter for iterating through the string.

3. User Input:

   • The program prompts the user to enter a string, which is read using fgets(). This function allows spaces in the input.

4. Character Iteration:

   • A while loop is used to iterate through each character of the string until the null terminator ('\0') is reached.

5. Character Processing:

   • Each character is converted to lowercase using tolower() for uniform comparison.
   • The isalpha() function checks if the character is a letter.
   • If the character is a vowel (checked against 'a', 'e', 'i', 'o', 'u'), the vowel counter is incremented.
   • If it is not a vowel but is an alphabetic character, the consonant counter is incremented.

6. Display Results:

   • After iterating through the string, the program prints the total counts of vowels and consonants.

How to Run the Program

1. Compile the Code: Use a C compiler like gcc to compile the code.

   gcc count_vowels_consonants.c -o count_vowels_consonants
   

2. Execute the Program:

   ./count_vowels_consonants
   

3. Input Data: Enter a string when prompted.

Example Input/Output

Input:

Enter a string: Hello World!

Output:

Vowels: 3
Consonants: 7

Conclusion

The Count Vowels and Consonants program in C is a practical exercise that demonstrates how to manipulate strings and utilize character handling functions. It reinforces the understanding of loops, conditionals, and basic string operations in C programming. This type of program can be easily extended or modified to include additional functionality, such as counting specific letters or ignoring certain characters.