C Array of Structures

In C, you can use arrays to store multiple instances of structures. This is particularly useful when dealing with a collection of related data, such as student records, employee details, or product inventories.

Why Use an Array of Structures?

Syntax

The general syntax for an array of structures:

                        
struct StructureName {
    data_type member1;
    data_type member2;
    ...
};
        
struct StructureName arrayName[array_size];

Example: Basic Array of Structures

Here's a basic example that demonstrates how to use an array of structures:

Example 1:

                        
#include <stdio.h>
#include <string.h>
struct Student {
    int id;
    char name[50];
    float marks;
};

int main() 
{
    struct Student students[3];

    // Assigning values
    students[0].id = 1;
    strcpy(students[0].name, "Alice");
    students[0].marks = 85.5;

    students[1].id = 2;
    strcpy(students[1].name, "Bob");
    students[1].marks = 92.0;

    students[2].id = 3;
    strcpy(students[2].name, "Charlie");
    students[2].marks = 78.9;

    // Displaying values
    for (int i = 0; i < 3; i++) {
        printf("Student ID: %d\n", students[i].id);
        printf("Name: %s\n", students[i].name);
        printf("Marks: %.2f\n\n", students[i].marks);
    }        
        
        
    return 0;
}

Output:

Student ID: 1
Name: Alice
Marks: 85.50

Student ID: 2
Name: Bob
Marks: 92.00

Student ID: 3
Name: Charlie
Marks: 78.90

Array of Structures with Functions

Using functions, you can make the code modular by passing the array of structures to a function for processing:

Example 2:

                        
#include <stdio.h>
#include <string.h>
struct Employee {
    int id;
    char name[50];
    float salary;
};

void displayEmployees(struct Employee employees[], int size) {
    for (int i = 0; i < size; i++) {
        printf("Employee ID: %d\n", employees[i].id);
        printf("Name: %s\n", employees[i].name);
        printf("Salary: %.2f\n\n", employees[i].salary);
    }
}

int main() 
{
    struct Employee employees[2];

    // Assigning values
    employees[0].id = 101;
    strcpy(employees[0].name, "John");
    employees[0].salary = 50000.5;

    employees[1].id = 102;
    strcpy(employees[1].name, "Jane");
    employees[1].salary = 60000.7;

    // Displaying values using a function
    displayEmployees(employees, 2);
        
        
    return 0;
}

Output:

Employee ID: 101
Name: John
Salary: 50000.50

Employee ID: 102
Name: Jane
Salary: 60000.70

Key Points