int islower ( int c );

<cctype>

Check if character is lowercase letter

Checks if parameter c is a lowercase alphabetic letter.

Notice that what is considered a letter may depend on the locale being used; In the default C locale, a lowercase letter is any of: a b c d e f g h i j k l m n o p q r s t u v w x y z.

For a detailed chart on what the different ctype functions return for each character of the standard ANSII character set, see the reference for the <cctype> header.

Parameters

c

Character to be checked, casted to an int, or EOF.

Return Value

Example

/* islower example */
#include <stdio.h>
#include <ctype.h>
int main ()
{
  int i=0;
  char str[]="Test String.\n";
  char c;
  while (str[i])
  {
    c=str[i];
    if (islower(c)) c=toupper(c);
    putchar (c);
    i++;
  }
  return 0;
}

Output:

TEST STRING.

See also