tolower

From:http://www.cplusplus.com/reference/clibrary/cctype/tolower/

#include <ctype.h>

or

#include <cctype>

tolower

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

/* tolower example */

#include <stdio.h>

#include <ctype.h>

int main(void)

{

    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.