Write a C program to check whether an alphabet is a vowel or consonant

In this post, you will learn how to write a C program to check whether an alphabet is a vowel or a consonant.

The alphabet is made up of 26 letters, 5 of which are vowels (a, e, i, o, u) and the rest of which are consonants. There are different ways in C programming to check whether an alphabet is a vowel or consonant.

Using If Else statement

The given C program allows the user to enter any character and check whether the given alphabet is a vowel or consonant using the if else statement.

#include <stdio.h>
int main()
{
  char ch;

  printf("Please enter a character\n");
  scanf("%c", &ch);

  if (ch == 'a' || ch == 'A' || ch == 'e' || ch == 'E' || ch == 'i'
      || ch == 'I' || ch =='o' || ch=='O' || ch == 'u' || ch == 'U')
    printf("%c is a vowel.\n", ch);
  else
    printf("%c is not a vowel.\n", ch);

  return 0;
}

The character entered by the user is stored in a variable ch. Next, we have used the If Else statement to check whether the user entered character is equal to a, e, i, o, u, A, E, I, I, O. If it is TRUE, it is a vowel otherwise a consonant.

Please enter a character
A
A is a vowel.

Please enter a character
g
g is not a vowel.

Using switch statement

In the given C program, we have used the switch statement to check whether the entered alphabet is consonant or vowel.

#include <stdio.h>
 
int main()
{
  char ch;

  printf("Enter an alphabet : ");
  scanf("%c", &ch);

  switch(ch)
  {
    case 'a':
    case 'A':
    case 'e':
    case 'E':
    case 'i':
    case 'I':
    case 'o':
    case 'O':
    case 'u':
    case 'U':
      printf("%c is a vowel.\n", ch);
      break;
    default:
      printf("%c is not a vowel.\n", ch);
  }
  return 0;
}

Enter an alphabet : s
s is not a vowel.

Enter an alphabet : I
I is a vowel.

Using user defined function

Here, we have checked whether a character is a consonant or not using a user-defined function. If it's not a vowel, then it is a consonant, but make sure that it's an alphabet, not a special character.

// C Program to check whether
// an alphabet is vowel or consonant

#include <stdio.h>
int check_vowel(char a);
int main()
{
    char ch;
    printf("Please enter an alphabet: \n");
    scanf(" %c", &ch);

    if(check_vowel(ch))  {
		printf("%c is a vowel.", ch);
	}
    else {
    	printf("%c is a consonant.", ch);
	}
    return 0;
}

int check_vowel(char c)
{
    if (c >= 'A' && c <= 'Z')
       c = c + 32;

    if (c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u')
       return 1;

    return 0;
}

Please enter an alphabet:
A
A is a vowel.

Please enter an alphabet:
P
P is a consonant.

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