What is the purpose of a C language union?

Unions in C language are primarily used to conserve memory space by allowing different types of data to be stored in the same memory location. Unlike structures, unions have members that share the same memory space.

The main functions of the alliance are as follows:

1. Save memory space: Members within a union share the same memory space, with only one member being able to store data, so the size of memory occupied by the union is equal to the size of the largest member.
2. Conversion of data types can be achieved by using unions, which allow for different types of data to be transformed. Accessing one member can provide the value of another member.
3. For unions: Unions can be used for implementing unions. A union is a special type of a union where all its members begin at the same starting location, sharing the same memory space.
4. The use of unions for bit fields: Unions can be used to implement bit fields. Bit fields are a technique used to store multiple different data in a byte (or larger storage unit), and unions can facilitate the implementation of bit fields.

In conclusion, the purpose of a union is to store different types of data in the same memory space, saving memory and enabling functions like data type conversion, unions, and bit-fields.