Structures Basics

Structures in C++ are user-defined data types that allow you to combine different types of data into a single unit. They are useful for organizing related information together.

What is a Structure?

A structure (struct) is a collection of variables of different data types grouped under one name.

For example, a student may have:

• Name
• Age
• Marks

Instead of creating separate variables, a structure stores them together.

Why Use Structures?

Structures are useful because they:

• Organize related data
• Reduce code complexity
• Improve readability
• Represent real-world entities

Syntax of Structure

struct StructureName {
    data_type member1;
    data_type member2;
};

Example of Structure

#include <iostream>
using namespace std;

struct Student {
    string name;
    int age;
    float marks;
};

int main() {

    Student s1;

    s1.name = "Ali";
    s1.age = 18;
    s1.marks = 85.5;

    cout << s1.name << endl;
    cout << s1.age << endl;
    cout << s1.marks << endl;

    return 0;
}

Output

Ali
18
85.5

How Structures Work

• struct defines a custom data type
• Variables inside structure are called members
• Structure variables are called objects
• Members are accessed using the dot (.) operator

Accessing Structure Members

s1.name = "Ali";

Structure Initialization

You can initialize structure values directly.

Student s1 = {"Ahmed", 20, 90.5};

Array of Structures

Structures can also be used in arrays.

Student students[3];

Example of Array of Structures

#include <iostream>
using namespace std;

struct Student {
    string name;
    int age;
};

int main() {

    Student s[2];

    s[0].name = "Ali";
    s[0].age = 18;

    s[1].name = "Ahmed";
    s[1].age = 20;

    cout << s[0].name << endl;
    cout << s[1].name << endl;

    return 0;
}

Nested Structures

A structure can contain another structure.

struct Address {
    string city;
};

struct Student {
    string name;
    Address addr;
};

Structure with Functions

Structures can also contain functions in C++.

struct Demo {
    int x;

    void show() {
        cout << x;
    }
};

Difference Between Structure and Class

Structure	Class
Members are public by default	Members are private by default
Mainly used for simple data grouping	Used for full OOP concepts

Advantages of Structures

• Easy data organization
• Supports different data types together
• Improves code clarity
• Useful for records and databases

Why Structures are Important

Structures are important because they:

• Represent real-world objects
• Help manage complex data
• Support better program design
• Form the base of advanced concepts

Real-Life Example

Think of a student ID card:

• Name
• Roll number
• Class
• Marks

All related information is stored together, just like a structure.

Conclusion

Structures in C++ are powerful user-defined data types used to group related data together. They improve program organization, readability, and efficiency, making them essential for handling complex information in real-world applications.