ChapmIndustries ChapmIndustries - 4 months ago 44
C Question

tolower() Function not Working in C99

I am using the CS50 appliance from Harvard and trying to make a character lowercase. I am trying to use the

tolower()
function but when I try to use it I get the message
implicit declaration of function 'tolower' is invalid in C99
. Anyone care to elaborate on why I would be getting this message. I have included
stdio.h
as well as
string.h
.

Answer

To use tolower in C99, use #include <ctype.h>

It is not an I/O function and it doesn't operate on strings (it operates on characters), so it's not in stdio or string.