Why use a union over a struct?

Advantages of union It occupies less memory compared to structure. When you use union, only the last variable can be directly accessed. Union is used when you have to use the same memory location for two or more data members. It enables you to hold data of only one data member.

How is union better than structure?

Advantages of Union Union takes less memory space as compared to the structure. Only the largest size data member can be directly accessed while using a union. It is used when you want to use less (same) memory for different data members.

Where is union used in real time?

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.

What is the difference between structures and unions?

The structure and union both are the container data types that can hold data of any “type”. The one major difference that distinguishes structure and union is that the structure has a separate memory location for each of its members whereas, the members of a union share the same memory location.

What is structure and union with example?

A structure contains an ordered group of data objects. Each data object in a structure is a member or field. A union is an object similar to a structure except that all of its members start at the same location in memory. A union variable can represent the value of only one of its members at a time.

Why do we use unions in C?

C unions are used to save memory. To better understand an union, think of it as a chunk of memory that is used to store variables of different types. C unions allow data members which are mutually exclusive to share the same memory. This is quite important when memory is valuable, such as in embedded systems.

What are the uses of structure?

A structure is a collection of variables of same or different datatypes. It is useful in storing or using informations or databases. Example: An employee’s record must show its salary, position, experience, etc. It all can be stored in one single variable using structures.

What is the similarity between structure and union?

Similarities between Structure and Union Both structures and unions support only assignment = and sizeof operators. The two structures or unions in the assignment must have the same members and member types. A structure or a union can be passed by value to functions and returned by value by functions.

Why do you use structure?

A structure is used to represent information about something more complicated than a single number, character, or boolean can do (and more complicated than an array of the above data types can do). For example, a Student can be defined by his or her name, gpa, age, uid, etc.

When to use structs and unions?

You use a structure when your “thing” should be a group of other things. For example, a union can be used for representing widgets or gizmos (with a field allowing us to know what it is), something like: struct { int isAGizmo; union { widget w; gizmo g; } }. In this example, w and g will overlap in memory.

How do you access the members of a union?

Like structures, we can have pointers to unions and can access members using the arrow operator (->). The following example demonstrates the same. What are applications of union? Unions can be useful in many situations where we want to use the same memory for two or more members.

When should I use a structure?

You use a structure when your “thing” should be a group of other things. For example, a union can be used for representing widgets or gizmos (with a field allowing us to know what it is), something like: In this example, w and g will overlap in memory.

What are anonymous unions/structures?

Anonymous unions/structures are also known as unnamed unions/structures as they don’t have names. Since there is no names, direct objects (or variables) of them are not created and we use them in nested structure or unions. Definition is just like that of a normal union just without a name or tag.