C - Convert an uppercase letter to lowercase

Question

A really simple program. I just want to turn an 'A' into an 'a', but output is giving me 'A'.

#include <stdio.h>

int main(void) {
    putchar(lower('A')); 

}

lower(a) 
int a; 
{
    if ((a >= 65) && (a >= 90))
        a = a + 32; 
    return a;  
}

Answer 1

You messed up the second part of your if condition. That should be a <= 90.

Also, FYI, there is a C library function tolower that does this already:

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

int main() {
    putchar(tolower('A'));
}