islower


function
<cctype> 
int islower ( int c );

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.

In C++, a locale-specific template version of this function (islower) exists in header <locale>.

Parameters

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


Return Value

A value different from zero (i.e., true) if indeed c is a lowercase alphabetic letter. Zero (i.e., false) otherwise.

Example

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/* 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

isupper Check if character is uppercase letter (function)
isalpha Check if character is alphabetic (function)
toupper Convert lowercase letter to uppercase (function)
tolower Convert uppercase letter to lowercase (function)