C Program to check whether the Character is Alphabet or Digit

How to write a C Program to check whether the Character is Alphabet or Digit by using Built-in function isalpha, isdigit, and also not using any built-in function.

C Program to check whether the Character is Alphabet or Digit

This program allows the user to enter one character, and then it will check whether the user specified character is Alphabet or digit

/* C Program to check whether the Character is Alphabet or Digit */

#include <stdio.h>

int main()
{
  char ch;
  printf(" Please Enter any character :  ");
  scanf("%c", &ch);
  
  if( (ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z') )
  {
  	printf("\n %c is an Alphabet", ch);  	
  }
  else if (ch >= '0' && ch <= '9')
  {
  	printf("\n %c is a Digit", ch);  	
  }    
  else
    printf("\n %c is not an Alphabet, or a Digit", ch);
  
  return 0;
}

OUTPUT

Let us check whether 7 is an Alphabet or Digit

Let us check whether $ is an Alphabet or not (which is not TRUE)

Program to check whether the Character is Alphabet or Digit 2

In this program, we are using the ASCII values to check whether the input character is Alphabet or Digit. I suggest you refer ASCII Table to under the ascii values of each and every character.

/* C Program to check whether the Character is Alphabet or Digit */

#include <stdio.h>

int main()
{
  char ch;
  printf(" Please Enter any character :  ");
  scanf("%c", &ch);
  
  if (ch >= 48 && ch <= 57)
  {
  	printf("\n %c is a Digit", ch);  	
  }
  else if ( (ch >= 65 && ch <= 90) || (ch >= 97 && ch <= 122) )
  {
  	printf("\n %c is an Alphabet", ch);  	
  }    
  else
    printf("\n %c is not an Alphabet, or a Digit", ch);
  
  return 0;
}

OUTPUT

Let us check whether # is an Alphabet or not (Not TRUE)

Let us check whether g is an Alphabet or not (TRUE)

Program to check whether the Character is Alphabet or Digit 3

In this program, we are using the built-in functions isalpha, and isdigit to check whether the input character is Alphabet or Digit

/* C Program to check whether the Character is Alphabet or Digit */

#include <stdio.h>

int main()
{
  char ch;
  printf(" Please Enter any character :  ");
  scanf("%c", &ch);
  
  if (isdigit(ch))
  {
  	printf("\n %c is a Digit", ch);  	
  }
  else if ( isalpha(ch) )
  {
  	printf("\n %c is an Alphabet", ch);  	
  }    
  else
    printf("\n %c is not an Alphabet, or a Digit", ch);
  
  return 0;
}

OUTPUT