Difference between Structure and Array in C

In C, both structures and arrays are used as containers to store data. The key difference is that a structure can hold variables of different data types, while an array can only hold variables of the same data type.

Example

The following example demonstrates the difference between a structure and an array in C ?

#include <stdio.h>

// Structure: holds different data types
struct Student {
    char name[20];
    int age;
    float gpa;
};

int main() {
    // Structure usage
    struct Student s1 = {"Alice", 20, 3.85};
    printf("Structure:
");
    printf("  Name: %s
", s1.name);    // access by member name
    printf("  Age: %d
", s1.age);
    printf("  GPA: %.2f
", s1.gpa);

    // Array usage: holds same data type only
    int scores[] = {85, 92, 78, 95, 88};
    printf("\nArray:
");
    int i;
    for (i = 0; i < 5; i++) {
        printf("  scores[%d] = %d
", i, scores[i]);  // access by index
    }

    return 0;
}

The output of the above code is ?

Structure:
  Name: Alice
  Age: 20
  GPA: 3.85

Array:
  scores[0] = 85
  scores[1] = 92
  scores[2] = 78
  scores[3] = 95
  scores[4] = 88

Key Differences

Conclusion

Use a structure when you need to group related data of different types (like a student record with name, age, and GPA). Use an array when you need to store multiple values of the same type (like a list of scores) with fast index-based access.