I'm trying to understand how the isupper function in c works. From what I've read, it checks if a character is an uppercase letter, but I'd like to clarify a few things:
What does isupper return if the input is not an uppercase letter?
Do I need to include a specific header file for it?
Can isupper be used with non-ASCII characters?
Here's an example I'm testing:
c
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Edit
#include <stdio.h>
#include <ctype.h>
void check_char(char ch) {
if (isupper(ch)) {
printf("%c is uppercase.\n", ch);
} else {
printf("%c is not uppercase.\n", ch);
}
}
int main() {
check_char('Z');
check_char('a');
check_char('5');
return 0;
