C Array

array.c

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

#define Array(Type) struct array_##Type
#define DefineArray(Type) struct array_##Type { Type* elements; int len; int cap; }
#define array_get(array, index) (array).elements[index]
#define array_set(array, value, index) (array).elements[index] = value
#define create_Array(Type, cap) (struct array_##Type) { (Type*) malloc(cap * sizeof(Type)), 0, cap }
#define destroy_Array(array) free((array).elements)
#define array_append(array, value) (array).elements[(array).len++] = value
#define array_append_checked(Type, array, value) array_reserve(Type, array); array_append(array, value)
// Reserve minimum capacity
#define array_reserve_capacity(Type, array, newCap) if ((array).cap < newCap) { \
    array_set_capacity(Type, array, newCap) \
}
// Set the capacity without checks
#define array_set_capacity(Type, array, newCap) \
    array.cap = newCap; \
    array.elements = (Type*) realloc(array.elements, array.cap * sizeof(Type));
// Allocate more when all elements in the array are full
#define array_reserve(Type, array) if ((array).cap == (array).len) { \
    array_set_capacity(Type, array, (array).cap * 2) \
}

DefineArray(int);

int main()
{
    Array(int) a = create_Array(int, 1);
    array_append_checked(int, a, 1);
    array_append_checked(int, a, 2);
    array_append_checked(int, a, 4);
    printf("cap = %d\n", a.cap);
    array_reserve_capacity(int, a, 100);
    printf("cap = %d\n", a.cap);
    array_append(a, 10);
    
    for (int i = 0; i < a.len; i++) {
        int value = a.elements[i];
        printf("%d\n", value);
    }
    array_set(a, 5, 1);
    printf("%d\n", array_get(a, 1));

    return 0;
}