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C Library
cassert (assert.h)
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climits (limits.h)
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csignal (signal.h)
cstdarg (stdarg.h)
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cctype (ctype.h)
isalnum
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tolower
toupper


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