#include <iostream>
using namespace std;
 
void passPointer(int *x);
 
int main()
{
    int value = 10;
    int* vPtr = &value;
 
    std::cout << "value before function call: " << value << '\n';
    std::cout << "Address contained by vPtr before function call: " << vPtr << '\n';
 
    passPointer(vPtr);
 
    std::cout << "value after function call: " << value << '\n';
    std::cout << "Address contained by vPtr after function call: " << vPtr << '\n';
}
 
void passPointer(int *x){
    int local_variable;
 
    std::cout << "Address of local_variable: " << &local_variable << '\n';
 
    *x = 20;                    // derefence allows one to get a reference to the object pointed to.
    x = &local_variable;        // not dereferencing means we're modifying a copy of the pointer.
}

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