// An example of creating an array of a size
// determined at run time using malloc

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

int *create_array(int num_elements);
void print_array(int nums[], int size);


int main(void) {
    int num_elements;
    printf("How many elements? ");
    scanf("%d", &num_elements);
 
    int *data = create_array(num_elements);
    
    printf("Original Array: ");
    print_array(data, num_elements);
   

    // Decide we need a bigger array!
    // Common to double the size or 1.5 the size etc.
    int new_size = num_elements + 1;

    data = realloc(data, new_size*sizeof(int));
    
    data[new_size-1] = 9999;
    

    //printf("Realloced Array: ");
    print_array(data, new_size);

    free(data);
    return 0;
}


// returns a pointer to a malloced array
int *create_array(int num_elements) {
    int *data = malloc(num_elements *sizeof(int));
    if (data == NULL) {
        printf("Out of memory\n");
        return NULL;
    }
    // You can still use array notation!!!!
    for (int i = 0; i < num_elements; i++) {
        data[i] = i*10;
    }
    return data;
}

void print_array(int nums[], int size) {
    for (int i = 0; i < size; i++) {
        printf("%d ", nums[i]);
    }
    printf("\n");
}