int Keyword Data type Range (varies) ??32,768 to +32,767 unsigned o to 65,535 Array declaration num [ x ] int num, age, num2; unsigned int num; isalnum( c ) <ctype.h> Returns True if c is a letter or digit if(isalnum( c )) isalpha( c ) <ctype.h> letter isascii( c ) <ctype.h> ASCII between 0???? ?? 127 iscntrl( c ) <ctype.h> delete char, or ordinary control char isdigit( c ) <ctype.h> Digit.