Include <ctype.h> header file contains function summary

The functions contained in the main are:

1. Character test function, function prototype is generally: int isxxxx (int);

The parameter is int and can only be handled correctly [0, 127].

2. Character mapping function, function prototype is generally: int toxxxx (int);

parameter detection, if the scope of the conversion, otherwise unchanged

int tolower (int); ' A ' ~ ' Z ' ==> ' a ' ~ ' Z '//first determine if it is a lowercase letter, if not, convert it to a lowercase letter (simple memory: to lower

int toupper (int); ' A ' ~ ' Z ' ==> ' a ' ~ ' Z '//first determine if it is not an uppercase letter, if not, convert it to uppercase (simple memory: to Upper  3. Determine the letter function:int isalpha (char ch);returns "Not 0" if Ch is a letter, otherwise returns 0. (Précis-writers: is Alpha?) )
   4. Determine if the control character function is not:int Iscntrl (char ch);Check if CH controls the character (its ASCII code is between 0 and 0x1f and the value is 0-31). (Précis-writers: is Cntrl?)   5. Determine the number function:int isdigit (char ch);If CH is a number then return "not 0", otherwise return 0. (Précis-writers: is digit?) )　6. Determine the lowercase letter function:int islower (char ch);yes returns "Not 0", otherwise returns 0.  7. Determine the uppercase function:int isupper (char ch);yes returns "Not 0", otherwise returns 0.  8. Also determine whether it is a function of letters or numbers:int isalnum (char ch);yes returns "Not 0", otherwise returns 0. (Précis-writers: is Al or num?) (Remember these first ~ ~ ~)!          

Include <ctype.h> header file contains function summary