To count the number of vowels in a word

Introduction

Each time you see a vowel, add one. For example:

because.

b (no) e (+1=1) c (no) a (+1=2) u (+1=3) s (no) e (+1=4)

One way of doing this is to scan the string "because" from left to right. We read in a character, and check if it is a vowel. The character is compared to a dictionary of vowels. This "dictionary" is stored in the line

   static const char vowels[] = "aeiouAEIOU";

so in this code, the lowercase and uppercase letters are all vowels.

The code

include <stdio.h>
include <string.h>

/* main: main loop for counting vowels in word */ int main(void) {

   size_t i, j, word_len, vowels_len;
   int vowel_count;
   char word[21];   /* 20 + '\0' */
   static const char vowels[] = "aeiouAEIOU";

   printf("Enter a word: ");
   scanf("%20s", word);

   /* initialise variables */
   word_len   = strlen(word);     
   vowels_len = strlen(vowels);
   vowel_count = 0;

   for (i = 0; i < word_len; ++i) {         /* loop through word   */
       for (j = 0; j < vowels_len; ++j) {   /* loop through vowels */
          if (word[i] == vowels[j]) {
              ++vowel_count;
              break;
          }
       }
   }

   printf("\nThe no. of vowels in '%s' is %d\n", word, vowel_count);

   /* indicate success */
   return 0;

} </source>

Line by line explanation

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