DifferencesTerms And Technology

Difference between union and structure with table

We explain the difference between structure and union with table. Structure and union are used in the world of programming to facilitate the function of variables, the flow of data, and the ability to manipulate data. Managing variables is a very important process, as it helps us define complex algorithmic structures that can process data. In the same way, the C programming language offers two types of variables, called structure and union. difference between union and structure

At first glance, they both seem to have quite similar functions, and in some cases they can also be used for the same function! However, there are several differences that these have, knowing which one helps to differentiate these terms.

What is the structure?

Structures are variables that can hold many types of data items at the same time. However, it is worth noting that the data elements that a structure contains can be of different data types. Therefore, the structure is a very useful way for storing, accessing and manipulating data. A structure is defined by the ‘struct’ declaration. difference between union and structure

To understand what a keyword is, we will have to analyze the concept of language a bit. In any programming language, not just C, we need to use a keyword or command that helps the compiler to recognize a certain function that has been called and will execute accordingly. difference between union and structure

The syntax of a structure follows the following pattern:

struct structure_name {

char firstName [10];

char lastName [10];

Int age;

address char [20];


This structure has been named ‘structure_name’ and can be called anywhere in the function once defined. It can also be called multiple times, depending on the requirement. We can see that the structure has some data elements as attributes.

They are a person’s first name, that person’s last name, their age, and their address. Notice how there is more than one data type present in the structure. All of these data types will have separate memory locations where they will be stored. difference between union and structure

By default, all members of a structure are public. By public, we mean that all other functions and objects will be able to access all the data types that are present in the structure. However, this property can be changed to private to protect the data.

What is Union?

A union is a data type that can store multiple data items within it. This is found in the C programming language, where it helps in the insertion, manipulation, and access of data in a program. However, it is worth noting that joins cannot contain data elements of different data types, so this limits their capabilities compared to structures to some extent.

When we define or call a join, it is pretty much the same method as we call a structure. The keyword for union is just ‘union’, and this is followed by the name of the union that the programmer wants to give. The union syntax is as follows:difference between union and structure

union union_name {

Data object 1;

Data object 2;



Similar to structures, the union, after being defined, can be used anywhere in the function and also in other classes and objects. The union can be used as many times as necessary. The memory space occupied by the join will be the same as the memory required to accommodate the largest data type mentioned in the join. difference between union and structure

The difference between structure and union is that separate memory locations are assigned to each member of a structure, however, a union contains a single memory location for all its data contents. difference between union and structure

Comparison table between structure and union

Comparison parameters Structure Union
Definition The structure assigns different items to different memory locations. Union allocates different memory elements to the same location.
Syntax struct struct1 {Data type 1; Data type 2;…} variable 1, variable 2,…; union union1 {Data type 1; Data type 2;…} variable1; variable2,…;
Keyword structure Union
Memory All data types are in separate memory locations. All data types are in the same memory location.
Size Storage size is the sum of the size of all data items. The storage size is the value of the largest data type.

Main differences between structure and union

  1. The main difference between Structure and Union is that structures are variables that can accommodate other variables and allocate separate memory spaces to them, while unions allocate the same memory space to variables.
  2. The structure keyword is ‘structure’, while the join keyword is ‘join’. difference between union and structure
  3. Structures can store multiple values ​​at a time, while unions can store only one value at a time.
  4. Structures can help you view a single memory location in only one way. Unions help you see a single memory location in many ways.
  5. A structure cannot be anonymous, however a join can be declared anonymous.

Final Thought

The various functions, objects, and characteristics of a programming language define whether it will be useful to the programmer or not. Languages ​​have different characteristics, which define what it will do. Some languages ​​are better designed for developing web pages, some are designed for developing games, some for developing high-performance software, and some for Android applications. difference between union and structure

There are numerous purposes for numerous languages. The fact that some languages ​​are object-oriented, while others are program-oriented. Object-oriented languages ​​help us add and remove modules. This makes it easy to create software, which helps us make our lives easier.difference between union and structure

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