C Program to Check Whether a Character is a Vowel or Consonant | by Programadecode SoftwareTechIT

 

C Program to Check Whether a Character is a Vowel or Consonant

In this example, you will learn to check whether an alphabet entered by the user is a vowel or a consonant.

To understand this example, you should have the knowledge of the following C programming topics:

·         C Programming Operators

·         C if...else Statement

·         C while and do...while Loop

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The five letters A, E, I, O and U are called vowels. All other alphabets except these 5 vowels are called consonants.

This program assumes that the user will always enter an alphabet character.

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Program to Check Vowel or consonant

#include <stdio.h>

int main() {

    char c;

    int lowercase_vowel, uppercase_vowel;

    printf("Enter an alphabet: ");

    scanf("%c", &c);

    // evaluates to 1 if variable c is a lowercase vowel

    lowercase_vowel = (c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u');

    // evaluates to 1 if variable c is a uppercase vowel

    uppercase_vowel = (c == 'A' || c == 'E' || c == 'I' || c == 'O' || c == 'U');

    // evaluates to 1 (true) if c is a vowel

    if (lowercase_vowel || uppercase_vowel)

        printf("%c is a vowel.", c);

    else

        printf("%c is a consonant.", c);

    return 0;

}

Output

Enter an alphabet: G

G is a consonant.

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The character entered by the user is stored in variable c.

The lowercase_vowel variable evaluates to 1 (true) if c is a lowercase vowel and 0 (false) for any other characters.

Similarly, the uppercase_vowel variable evaluates to 1 (true) if c is an uppercase vowel and 0 (false) for any other character.

If either lowercase_vowel or uppercase_vowel variable is 1 (true), the entered character is a vowel. However, if both lowercase_vowel and uppercase_vowel variables are 0, the entered character is a consonant.

Note: This program assumes that the user will enter an alphabet. If the user enters a non-alphabetic character, it displays the character is a consonant.

To fix this, we can use the isalpha() function. The islapha() function checks whether a character is an alphabet or not.

#include <ctype.h>

#include <stdio.h>

int main() {

   char c;

   int lowercase_vowel, uppercase_vowel;

   printf("Enter an alphabet: ");

   scanf("%c", &c);

   // evaluates to 1 if variable c is a lowercase vowel

   lowercase_vowel = (c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u');

   // evaluates to 1 if variable c is a uppercase vowel

   uppercase_vowel = (c == 'A' || c == 'E' || c == 'I' || c == 'O' || c == 'U');

   // Show error message if c is not an alphabet

   if (!isalpha(c))

      printf("Error! Non-alphabetic character.");

   else if (lowercase_vowel || uppercase_vowel)

      printf("%c is a vowel.", c);

   else

      printf("%c is a consonant.", c);

   return 0;

}

Now, if the user enters a non-alphabetic character, you will see:

Enter an alphabet: 3

Error! Non-alphabetic character.

 

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