C Language: isalpha function
(Test for Alphabetic)
In the C Programming Language, the isalpha function tests whether c is alphabetic.
Syntax
The syntax for the isalpha function in the C Language is:
int isalpha(int c);
Parameters or Arguments
- c
- The value to test whether it is alphabetic.
Note
- c is considered to be alphabetic if either islower(c) is true or isupper(c) is true.
Returns
The isalpha function returns a nonzero value if c is alphabetic and returns zero if c is not alphabetic.
Required Header
In the C Language, the required header for the isalpha function is:
#include <ctype.h>
Applies To
In the C Language, the isalpha function can be used in the following versions:
- ANSI/ISO 9899-1990
isalpha Example
/* Example using isalpha by TechOnTheNet.com */
#include <stdio.h>
#include <ctype.h>
int main(int argc, const char * argv[])
{
/* Define a temporary variable */
unsigned char test;
/* Assign a test letter to the variable */
test = 'T';
/* Test to see if this is a alphabet character */
if (isalpha(test) != 0) printf("%c is in the alphabet\n", test);
else printf("%c is not in the alphabet\n", test);
/* Assign a non-alphabetic character to the variable */
test = '7';
/* Test to see if this is a alphabet character */
if (isalpha(test) != 0) printf("%c is in the alphabet\n", test);
else printf("%c is not in the alphabet\n", test);
return 0;
}
When compiled and run, this application will output:
T is in the alphabet 7 is not in the alphabet
Similar Functions
Other C functions that are similar to the isalpha function:
See Also
Other C functions that are noteworthy when dealing with the isalpha function:
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