exo4

void * person__copy(void const * p)
{
    struct person *ret = malloc(sizeof(struct person));
    if(ret == NULL)
        return NULL;

    struct person *param = (struct person*)p; //cast
    ret->age = param->age;

    ret->name = malloc( strlen(param->name) + 1); //carac final
    strcpy(ret->name, param->name);

    return (void*)ret; //cast back
}