Array of structs

Learn arrays of structs and sorting them.

Array of structs

The natural way to manage multiple structs is an array of structs. This is the core pattern for record lists, tables and collections.

Example: struct Person people[3];. Access: people[0].age = 30;. Here people[0] is a struct value; that's why the . operator is used. The array size must be fixed; dynamic size needs a pointer and malloc. Looping through all elements is common: for (int i = 0; i < 3; i++) printf("%d\n", people[i].age);.

Sorting with qsort

To sort an array of structs, you can use the standard qsort function. qsort takes a comparator callback; this combines the function pointer concept with structs.

Call: qsort(people, 3, sizeof(struct Person), compare);. Comparator signature: int compare(const void *a, const void *b). Inside you cast the pointer to struct Person*: struct Person *pa = (struct Person*)a;. Then return pa->age - pb->age. This pattern gives ascending sort by age.

Exercise Print a struct array

Define struct Person with char name[32]; and int age;. In main, declare struct Person people[3] = {{"Ali", 30}, {"Ayşe", 25}, {"Veli", 35}};. With a for loop, print each element's age field with printf("%d\n", people[i].age);.

Show example solution

#include <stdio.h>

struct Person {
    char name[32];
    int age;
};

int main(void) {
    struct Person people[3] = {{"Ali", 30}, {"Ayşe", 25}, {"Veli", 35}};
    for (int i = 0; i < 3; i++) {
        printf("%d\n", people[i].age);
    }
    return 0;
}

Test yourself

Match the array expressions

people[0].age

First element's field
people[i]

Indexed element
struct Person people[3]

Array declaration
people[2].name

Last element's field

Assign a field of an array element

struct Person people[3];
people[0]____ = 30;

Show answer

struct Person people[3];
people[0].age = 30;

To sort a struct array by age?
- strcpy
- malloc
- fopen
- qsort + comparator
Show answer

qsort + comparator — qsort takes a comparator callback and sorts the struct array.

Next lesson: Summary - Advanced structs

We Are Enhancing Your Experience

Cookie Preferences

Strictly Necessary Cookies

Analytical Cookies