W3Schools Tryit Editor

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

struct Car {
  char brand[50];
  int year;
};

int main() {
  int count = 2;
  struct Car *cars = (struct Car*) malloc(count * sizeof(struct Car));
  if (cars == NULL) {
    printf("Initial allocation failed.\n");
    return 1;
  }

// Initialize first 2 cars
  strcpy(cars[0].brand, "Toyota"); cars[0].year = 2010;
  strcpy(cars[1].brand, "Audi");   cars[1].year = 2019;

// Need one more car -> grow to 3
  int newCount = 3;
  struct Car *tmp = (struct Car*) realloc(cars, newCount * sizeof(struct Car));
  if (tmp == NULL) {
    // 'cars' is still valid here; free it to avoid a leak
    free(cars);
    printf("Reallocation failed.\n");
    return 1;
  }
  cars = tmp;  // use the reallocated block

// Initialize the new element at index 2
  strcpy(cars[2].brand, "Kia");
  cars[2].year = 2022;

// Print all cars
  for (int i = 0; i < newCount; i++) {
    printf("%s - %d\n", cars[i].brand, cars[i].year);
  }

free(cars);
  return 0;
}