Operands

Most expressions can contain several different, but related, types of operands. The following type classes described related types of operands.

integral	Character objects and constants, objects having an enumeration type, and objects having the types short, int, long, long long, unsigned short, unsigned int, unsigned long, or unsigned long long.
arithmetic	Integral objects listed above, and objects having the types float, double, long double, and long float.
scalar	Arithmetic objects listed above, and pointers to any object type. Also C++ references.
aggregate	Arrays, structures, and unions. Also C++ classes.

Many operators cause conversions from one data type to another.