ctype module

Provides character type identification and translation.

isupper

BYTE isupper(BYTE x);

Returns non-zero if x is an ASCII upper case character (A-Z), else returns 0.

 

islower

BYTE islower(BYTE x);

Returns non-zero if x is an ASCII lower case character (a-z), else returns 0.

 

isalpha

BYTE isalpha(BYTE x);

Returns non-zero if x is a ASCII upper or lower case character (A-Z,a-z), else returns 0.

 

isalphanum

BYTE isalphanum(BYTE x);

Returns non-zero if x is a ASCII upper or lower case character or a decimal digit (A-Z,a-z,0-9), else returns 0.

 

isdigit

BYTE isdigit(BYTE x);

Returns non-zero if x is an ASCII decimal digit (0-9), else returns 0.

 

isxdigit

BYTE isxdigit(BYTE x);

Returns non-zero if x is an ASCII hexadecimal digit (0-9,a-f,A-F), else returns 0.

 

isspace

BYTE isspace(BYTE x);

Returns non-zero if x is a ASCII space character (space, vertical tab, horizontal tab, form feed, carriage return or newline), else returns 0.

 

isprint

BYTE isprint(BYTE x);

Returns non-zero if x is an ASCII printable character (0x20-0x7e), else returns 0.

 

isgraph

BYTE isgraph(BYTE x);

Returns non-zero if x is an ASCII printable character other than a space (0x21-0x7e), else returns 0.

 

toupper

BYTE toupper(BYTE x);

If x is a lower case character, then return the upper case equivalent, else return x.

 

tolower

BYTE tolower(BYTE x);

If x is an uppercase ASCII character, then return the lower case equivalent, else return x.