C tolower() function

C tolower(int c)

The tolower() function is used to translate uppercase characters to lowercase characters. The function is defined in the ctype.h header file.

Syntax:

int tolower(int argument);

tolower() Parameters:

Return value from tolower()

• Upon successful completion, tolower() returns the lowercase letter corresponding to the argument passed; otherwise returns the argument unchanged.

Example: How tolower() function works?

#include <stdio.h>
#include <ctype.h>

int main() {
    char ch;
     printf("Convert upper case to lower case:\n");
    ch = 'W';
    printf("%c -> %c", ch, tolower(ch));

    ch = 'x';
    printf("\n%c -> %c", ch, tolower(ch));
    ch = 'Y';
    printf("\n%c -> %c", ch, tolower(ch));
    ch = 'A';
    printf("\n%c -> %c", ch, tolower(ch));
    return 0;
}

Output:

Convert upper case to lower case:
W -> w
x -> x
Y -> y
A -> a

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