Character Handling Functions in C++ with Example

There are various character handling functions in C++ which provide facility to handle character in different ways.

C++ provides #include<ctype.h> header file for character handling.

All character functions have defined in #include<ctype.h> header file . “ctype” means charater type.

Character Functions

isalnum() :- This function is used to check whether a character is a letter or a digit i.e alphanumeric or not.
- syntax isalnum(ch);
isdigit():- This function is used to check whether a character is digit or not.
- syntax isdigit(ch);
isalpha():- This function is used to check whether a character is alphabet or not.
- syntax isalpha(ch);
islower():- This function is used to check whether a character is lowercase alphabet or not.
- syntax islower(ch);
isupper():- This function is used to check whether a character is uppercase or not.
- syntax isupper(ch);
tolower():- This function is used to convert uppercase character to lowercase character.
- syntax tolower(ch);
toupper():- This function is used to convert lowercase character to uppercase character.
- syntax toupper(ch);
isspace():- This function is used to check whether a character is white space (blank) or not.
- syntax ispace(ch);

Where ch is a character variable.

Note :

when a character function is used to check the condition then following cases may occur.

case 1: If condition is true then returns nonzero value.

case 2: If condition is false then returns zero.

Q.Write a program to represent isalnum( ) OR Write a program to check input character is alphabet numeric or not.