tolower


function
<cctype> 
int tolower ( int c );

Convert uppercase letter to lowercase

Converts parameter c to its lowercase equivalent if c is an uppercase letter and has a lowercase equivalent. If no such conversion is possible, the value returned is c unchanged.

Notice that what is considered a letter may depend on the locale being used; In the default C locale, an uppercase 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, which translate respectively to: 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.

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

Parameters

c
Uppercase letter character to be converted, casted to an int, or EOF.


Return Value

The lowercase equivalent to c, if such value exists, or c (unchanged) otherwise. The value is returned as an int value that can be implicitly casted to char.

Example

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/* tolower 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];
    putchar (tolower(c));
    i++;
  }
  return 0;
}


Output:
test string.


See also

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