Functions to deal with character

A lot of useful functions for dealing with characters can be found in the library cctype:

Funstion	Funcionality
isalpha(c);	Returns true if c is a letter (a-z, A-Z)
isupper(c);	Returns true if c is an upper-case letter
islower(c);	Returns true if c is a lower-case letter
isdigit(c);	Returns trud if c is a number(0-9)
isspace(c);	Returns true if c is a white space character
ispunct(c);	Returns true if c is a punctuation mark
toupper(c);	If c is a lower-case letter a upper-case letter is returned, otherwise c is returned
tolower(c);	If c is a upper-case letter a lower-case letter is returned, otherwise c is returned

These can be used by adding #include <cctype> to the includes.

However, the return type and the type of the parameter of these functions is int. This can cause problems in some systems. A safe way to use the functions is always explicitly cast the parameter to int with static_cast<int>( c ); The same can be done to the return type of the toupper and tolower to make sure the character value is correct.

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