hwo to allcoate and deallocate memory of pointer using libary

DYNAMICLIB_API int* aa1(void)
{
    int *a1;
    a1=(int*)malloc(sizeof(int));
    printf("Interger created\n");
    printf("bye");
    printf("good");
    printf("memory created");
     return a1;
}

int main(int argc, char* argv[])
{
    int *a1;
    a1=aa1();
    printf("Hello World!\n");
    free(a1);
    return 0;
}