Sizeof is an operator that can be used for any variable name, type name or constant value. When used for variable names (not array names) or constants, it does not need parentheses.

Sizeof has three grammatical forms.

1) is used for data types.

sizeof(type _ name)； // sizeof (type);

2) Used for variables

Sizeof (object); //sizeof(object)；

Sizeof object; // sizeof object;