Unions are useful for minimizing memory usage for exclusive data, such as when implementing mixed data types.
struct AnyType {
enum {
IS_INT,
IS_FLOAT
} type;
union Data {
int as_int;
float as_float;
} value;
AnyType(int i) : type(IS_INT) { value.as_int = i; }
AnyType(float f) : type(IS_FLOAT) { value.as_float = f; }
int get_int() const {
if(type == IS_INT)
return value.as_int;
else
return (int)value.as_float;
}
float get_float() const {
if(type == IS_FLOAT)
return value.as_float;
else
return (float)value.as_int;
}
};