ごめん>>860は不要。>>859と>>861だけ見てね。

#include <iostream>

struct A {
int a;
};

int main()
{
int* pi1 = new int();
int* pi2 = new int;
A* pa = new A();
A* pb = new A;

std::cout << *pi1 << std::endl; // ここだけ必ず 0
std::cout << *pi2 << std::endl;
std::cout << pa->a << std::endl;
std::cout << pb->a << std::endl;

delete pb;
delete pa;
delete pi2;
delete pi1;
}