C++ isalpha()
checks if given character is alphabet or not
C++ isblank()
checks if given character is a blank character
C++ iscntrl()
checks if given character is control character
C++ isdigit()
checks if given character is a digit or not
C++ isgraph()
checks if given character is graphic or not
C++ islower()
checks if given character is lowercase
C++ isprint()
check if given character is printable or not
C++ ispunct()
check if given character is punctuation character
C++ isspace()
check if given character is whitespace character
C++ isupper()
check if given character is uppercase or not
C++ isxdigit()
checks if given character is hexadecimal character
C++ tolower()
converts a given character to lowercase
C++ toupper()
converts a given character to uppercase