Lettercounter

lettercounter.c

// Count the number of letters in any given input

#include <stdio.h>


#define NUMBERS_IN_THE_ALPHABET 26
#define INPUT_BUFFER_LENGTH 1000
#define OUTPUT_BIG_LETTERS 1

// get an input line
size_t getInput(char* buffer, size_t* length)
{
    printf("Enter text: ");
    return getline(&buffer, length, stdin);
}

// main routine
int main(void)
{
    // we only check for alphabet letters
    int alphabet[NUMBERS_IN_THE_ALPHABET] = { 0 };
    
    // input of the user, max length is defined at the top
    char input[INPUT_BUFFER_LENGTH];
    // typedef unsigned long size_t
    size_t inputLength = INPUT_BUFFER_LENGTH;
    inputLength = getInput(input, &inputLength);
    
    // count letters
    for (size_t i = 0; i < inputLength; i++) {
        char c = input[i];
        
        // increase count
        if ( c >= 'a' && c <= 'z' ) {
            alphabet[c - 'a']++;
        } else if ( c >= 'A' && c <= 'Z' ) {
            alphabet[c - 'A']++;
        } else {
            if ( c == '\n' ) {
                continue;
            }
            printf("Not a character of the alphabet: %c\n", c);
        }
    }
    
    // output every letter
    for (unsigned int i = 0; i < NUMBERS_IN_THE_ALPHABET; i++) {
        char c = ( OUTPUT_BIG_LETTERS ) ? i + 'A' : i + 'a';
        
        printf("%c:\t%d\n", c, alphabet[i]);
    }
    
    // ok
    return 0;
}