isalpha Function

Test for an alphabetic character.

Include

<ctype.h>

Prototype

int isalpha(int c);

Argument

c

The character to test.

Return Value

Returns a non-zero integer value if the character is alphabetic; otherwise, returns zero.

Remarks

Alphabetic characters are included within the ranges A-Z or a-z.

Example

#include <ctype.h>
#include <stdio.h>

int main(void)
{
  int ch;

  ch = 'B';
  if (isalpha(ch))
    printf("B is alphabetic\n");
  else
    printf("B is NOT alphabetic\n");

  ch = '#';
  if (isalpha(ch))
    printf("# is alphabetic\n");
  else
    printf("# is NOT alphabetic\n");
}

Example Output

B is alphabetic
# is NOT alphabetic