![DEFINING A UNION
• To define a union, you must use the union statement in the same way as you
did while defining a structure.
• The union statement defines a new data type with more than one member for
your program. The format of the union statement is as follows −
union [union tag] {
member definition;
member definition;
...
member definition;
} [one or more union variables];](https://image.slidesharecdn.com/unionsinc-220825095024-f5752c9e/85/UNIONS-IN-C-pptx-3-320.jpg)
UNIONS IN C.pptx
- 1. UNIONS IN C
- 2. UNIONS • A union is a special data type available in C that allows to store different data types in the same memory location. • You can define a union with many members, but only one member can contain a value at any given time. • Unions provide an efficient way of using the same memory location for multiple-purpose.
- 3. DEFINING A UNION • To define a union, you must use the union statement in the same way as you did while defining a structure. • The union statement defines a new data type with more than one member for your program. The format of the union statement is as follows − union [union tag] { member definition; member definition; ... member definition; } [one or more union variables];
- 4. CREATING A UNION VARIABLE • When a union is defined, it creates a user-defined type. However, no memory is allocated. • To allocate memory for a given union type and work with it, we need to create variables. • The memory occupied by a union will be large enough to hold the largest member of the union
- 5. ACCESSING UNION MEMBERS • To access any member of a union, we use the member access operator (.). • The member access operator is coded as a period between the union variable name and the union member that we wish to access.
- 6. SIZE OF UNION • The size of the union is based on the size of the largest member of the union. • As we know, the size of int is 4 bytes, size of char is 1 byte, size of float is 4 bytes, and the size of double is 8 bytes. • Since the double variable occupies the largest memory among all the four variables, so total 8 bytes will be allocated in the memory. • Therefore, the output of the program would be 8 bytes.
- 7. ACCESSING MEMBERS USING POINTERS • We can access the members of the union through pointers by using the (->) arrow operator. • In the above code, we have created a pointer variable, i.e., *ptr, that stores the address of var variable. • Now, ptr can access the variable 'a' by using the (->) operator. • Hence the output of the above code would be 90.
- 11. 11