Hi, I have a question about the C++ pointer

int main() {

int num1 = 5, num2 = 6;

int *p1 = &num1;

int *p2 = &num2;

*p1 = 90;

std::cout << num1 << std::endl; // num1 unchanged, still 5

}

p1 is pointing to num1, and *p1 gets me the value stored on the address that p1 points (which is &num1), but why num1 is unchanged after *p1 = 90?

And how can I modify the value of num1 with the pointer p1?

Thank you, will upvote for detailed answer!