C++ Structures

A structure is a collection of variables of different data types under a single name.

It is similar to a class as both hold a collection of data of different data types.

For example: Suppose you want to store some information about a person: his/her name, citizenship number, and salary.

You can easily create different variables—name, citNo, salary—to store this information separately.

However, in the future, you might want to store information about multiple people.

Now, you'd need to create different variables for each information per person: name1, citNo1, salary1, name2, citNo2, salary2,

You can visualize how big and messy the code would look. Additionally, as there is no relation between the variables (information), it would be a daunting task to manage.

A better approach is to have a collection of all related information under a single name, such as Person and use it for every individual.

Now, the code looks much cleaner, more readable, and efficient as well.

This collection of all related information under a single name Person is a structure.

How to Declare a Structure in C++ Programming?

The struct keyword defines a structure type followed by an identifier (name of the structure).

Then, inside the curly braces, you can declare one or more members (declare variables inside curly braces) of that structure. For example:

struct Person
    char name[50];
    int age;
    float salary;

Here, the structure Person is defined which has three members: name, age, and salary.

When a structure is created, no memory is allocated.

The structure definition is only the blueprint for the creation of variables. You can imagine it as a data type.

When you define an integer as below:

int foo;

The int specifies that variable foo can hold integer elements only. Similarly, structure definition only specifies what property a structure variable holds when it is defined.

Note: Remember to end the declaration with a semicolon (;).

How to Define a Structure Variable?

Once you declare a structure Person as above, you can define a structure variable as:

Person bill;

Here, a structure variable bill is defined, which is of type structure Person.

Only when the structure variable is defined is the required memory allocated by the compiler.

Considering you have either a 32-bit or 64-bit system, the memory of float is 4 bytes, the memory of int is 4 bytes, and the memory of char is 1 byte.

Hence, 58 bytes of memory is allocated for the structure variable bill.

How to Access Members of a Structure?

The members of a structure variable are accessed using a dot (.) operator.

Suppose you want to access age of the structure variable bill and assign it 50 to it. You can perform this task by using the following code:

bill.age = 50;

C++ Structure

C++ Program to assign data to members of a structure variable and display it.

#include <iostream>
using namespace std;

struct Person
    char name[50];
    int age;
    float salary;

int main()
    Person p1;
    cout << "Enter Full name: ";
    cin.get(p1.name, 50);
    cout << "Enter age: ";
    cin >> p1.age;
    cout << "Enter salary: ";
    cin >> p1.salary;

    cout << "\nDisplaying Information." << endl;
    cout << "Name: " << p1.name << endl;
    cout <<"Age: " << p1.age << endl;
    cout << "Salary: " << p1.salary;

    return 0;


Enter Full name: Magdalena Dankova
Enter age: 27
Enter salary: 1024.4

Displaying Information.
Name: Magdalena Dankova
Age: 27
Salary: 1024.4

Here a structure Person is declared which has three members name, age and salary.

Inside the main() function, a structure variable p1 is defined. Then, the user is asked to enter information, and data entered by the user is displayed.

Also Read

Did you find this article helpful?