#include <iostream>

using namespace std;

int main()
{
    int x = 2;
    int *ptr = &x;
    (*ptr)++;
    cout << (*ptr);//prints out 3
}

VS

#include <iostream>

using namespace std;

int main()
{
    int x = 2;
    int *ptr = &x;
    ptr++;
    cout << (*ptr);  //undefined behavior, prints out what ever is in the memory spot after the address of x, which could be anything
}