Answer
A structure provides separate storage for every member, while union members overlap. • A structure can hold all member values simultaneously. • A union normally represents one active alternative at a time. • Both may contain padding and must follow alignment requirements.
💡 C Example
struct Pair { int left; int right; };
union Value { int integer; double real; };
⚡ Quick Revision
Structures store all members separately; unions share storage among alternatives.