#include <cstdlib>
#include <iostream>

using namespace std;

int main() {
   int a = 1;
   int b = 3;
   int x;
   int y;
   cout << "value of a: " << a << endl;
   cout << "value of b: " << b << endl;
   cout << "address of a:" << &a << endl;
   cout << "address of b:" << &b << endl;
   cout << "address of x:" << &x << endl;
   cout << "address of y:" << &y << endl;

   return 0;
}

// int main() {
//    int a = 3;
//    int* pa;
//    pa = &a;
//
//    int b = 4;
//    int* pb = &b;
//    int c = *pb;
//
//    cout << "c is: " << c << endl;
//
//    *pb = 101;
//
//    cout << "*pb is: " << *pb << endl;
//    cout << "b is: " << b << endl;
//
//    return 0;
// }

//int main() {
//    int a = 1;
//    int b = 2;
//    int* pa = &a;
//    cout << "a = " << a << " at address " << &a << endl;
//    cout << "b = " << b << " at address " << &b << endl;
//    cout << "pa = " << pa << " at address " << &pa << endl;
//    cout << "pa points to the value at address " << pa
//         << " which is " << *pa << endl;
//
//    return 0;
//}

//int main() {
//    int a = 70;
//    int b = 421;
//    int* pA;
//    int* pB;
//
//    pA = &a;
//    pB = pA;
//
//    cout << "a = " << a << " at address " << &a << endl;
//    cout << "b = " << b << " at address " << &b << endl;
//    cout << "pA = " << pA << " at address " << &pA << endl;
//    cout << "pA points to the value at address " << pA
//         << " which is " << *pA << endl;
//    cout << "pB = " << pB << " at address " << &pB << endl;
//    cout << "pB points to the value at address " << pB
//         << " which is " << *pB << endl;
//
//    // Do not do this:
//
//    // &a = pA;   // attempts to change the address of a
//    // pA = a;    // attempts to change pA to an invalid address
//    // *pA = pB;  // attempts to assign address to a signed integer
//    // pA = *pB;  // attempts to assign pA an invalid address
//
//    return 0;
//}

//int main() {
//   int x, y;
//   const int* px = &x; // value of pointer can't be changed
//   px = &y; // NOT OK ("change the value of px to this other address")
//   *px = 3; // ok ("change the value stored at the address pointed to")
//
//   const int* r = &x; // value of variable stored at
//                       // address pointed to can't be changed
//   r = &y; // ok ("change the value of px to this other address")
//   *r = 3; // NOT OK ("change the value stored at the address pointed to")
//
//   const int* const q = &x; // nothing associated w/ the pointer can change
//   q = &y; //disallowed
//   *q = 3; //disallowed
//
//   return 0;
//}

//int main() {
//    int x[4] = {100,200,300,400};
//    int *px = x;
//
//    cout << "x = " << x << " at address " << &x << endl;
//    cout << "px = " << px << " at address " << &px << endl;
//    cout << "px points to the value at address " << px
//         << " which is " << *px << endl;
//
//    ++px;
//    cout << "px = " << px << " at address " << &px << endl;
//    cout << "px points to the value at address " << px
//         << " which is " << *px << endl;
//
//    px = &x[2];
//    cout << "px = " << px << " at address " << &px << endl;
//    cout << "px points to the value at address " << px
//         << " which is " << *px << endl;
//
//    return 0;
//}