Union is an user defined datatype in C programming language . It is a collection of variables of different datatypes in the same memory location. We can define a union with many members, but at a given point of time only one member can contain a value.
What are unions in C++?
In C++17 and later, the std::variant class is a type-safe alternative for a union. A union is a user-defined type in which all members share the same memory location . This definition means that at any given time, a union can contain no more than one object from its list of members.