what is a char in c++ code example

Example 1: char c++

isdigit() - Check if character is decimal digit 
isalpha() - Check if character is alphabetic
isblank() - Check if character is blank
islower() - Check if character is lowercase letter
isupper() - Check if character is uppercase letter
isalnum() - Check if character is alphanumeric

Example 2: c++ char define

// syntax: 
// char <variable-name>[] = { '<1st-char>',  '<2nd-char>', ... , '<Nth-char>', '\0'}; 

// example (to store 'Hello' in the YourVar variable): 
char YourVar[] = {'H','e','l','l','o','\0'}; // NOTE: the \0 marks the end of the char array