isalpha.c File Reference

#include <ctype.h>

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Functions
int	isalpha (int c)
	Checks if the given character is an alphabetic character. More...

Function Documentation

isalpha()

int isalpha

(

int

ch

)

Checks if the given character is an alphabetic character.

Checks if the given character is an alphabetic character, i.e. either an uppercase letter (ABCDEFGHIJKLMNOPQRSTUVWXYZ), or a lowercase letter (abcdefghijklmnopqrstuvwxyz)

The behavior is undefined if the value of ch is not representable as unsigned char and is not equal to EOF.

Parameters

ch	The character to classify

Returns

Non-zero value if the character is an alphabetic character, zero otherwise.

Definition at line 5 of file isalpha.c.

{
    return ((unsigned)c | 32) - 'a' < 26;
}

Referenced by isalnum(), strtol(), strtoll(), and strtoul().

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