how to take char strig 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: working with char and string c++

String and Char