Generic in C using macros

.c

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

/*
 * Macro function that initializes a struct object
 * and returns it.
 *
 * For this to work, a `{type}Init` function must
 * be defined.
 */
#define STRUCT_INIT(type) ({ \
    struct type instance; \
    type ## Init((struct type*) &instance); \
    instance; \
})

struct User {
    char name[50];
    int age;
};
void UserInit(void* user) {
    memcpy(((struct User*)user)->name, "Rahul\0", 6);
    ((struct User*)user)->age = 40;
}

struct Account {
    char type[50];
    double balance;
};
void AccountInit(void* account) {
    memcpy(((struct Account*) account)->type, "Savings\0", 10);
    ((struct Account*) account)->balance = 10000000000.0;
}

int main() {
    struct User user = STRUCT_INIT(User);
    struct Account account = STRUCT_INIT(Account);

    printf("%s\n", user.name);
    printf("%d\n", user.age);

    printf("%s\n", account.type);
    printf("%f\n", account.balance); 

    return 0;
}