toupper - Convert lowercase letters to uppercase

Definition	#include <ctype.h> int toupper(int c); toupper converts the lowercase letter c to the corresponding uppercase letter.
Return val.	The uppercase letter corresponding to c
		if c is a lowercase letter.
	c unchanged	if c is not a lowercase letter.
Note	toupper is implemented both as a macro and as a function (see section “Functions and macros”).
Example	See example under tolower
See also	strupper, strlower, tolower, toascii, toebcdic, towupper