This documentation is copyright © 1998-2001 Sandro Sigala <sandro@sigala.it>.
All rights reserved.

Released under the GNU General Public License.

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islower

Prototype

#include <ctype.h>

int islower(int c);

Description

In the ``C'' locale, returns a true value for the characters defined as lowercase letters. In other implementation-defined set of characters returns true for the characters for which none of iscntrl, isdigit, ispunct, or isspace is true.

Example

View source
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>

/*
 * Count the lowercase, uppercase, and other characters read from
 * standard input.
 */
int main(void)
{
    int lower = 0, upper = 0, other = 0;
    int c;

    while ((c = getchar()) != EOF)
	if (islower(c))
	    ++lower;
	else if (isupper(c))
	    ++upper;
	else
	    ++other;

    printf("Lower case: %d, upper case: %d, other: %d\n",
	   lower, upper, other);

    return EXIT_SUCCESS;
}

References

ISO C 9899:1990 7.3.1.6