& Exchange function pointer references Practice

Practices are as follows:

#include <iostream>

using namespace std;

// Common exchange, the value of ab noted here, in particular when the call is a copy of the basic data, the original data does not change
 // thus the exchange value will not change here 
void the swap ( int A, int B) {
     int = tmp A;
    a = b;
    b = tmp;
}

// reference to the exchange, and the parameters of the original data point to the same place, can also be understood as a pointer to 
void refSwap ( int & A, int & B) {
     // need to define the value of the temporary variable tmp is stored 
    int tmp = A;
    a = b;
    b = tmp;
}

// pointer to the exchange, the original data point to the same parameters and a local 
void pointSwap ( int * A, int * B) {
     // need to define the value of the temporary variable tmp is stored 
    int tmp = * A;
     // pointer to the address value of the swap 
    * * = A B;
     * B = tmp;
}

int main () {

    COUT << " reference pointer swap function & Practice: " << endl;
     int A = . 11 ;
     int B = 22 is ;
    cout << " temporary variable exchange: " << endl;
    swap(a, b);
    cout << "a:" << a << endl;
    cout << "b:" << b << endl;

    COUT << " pass by reference exchange: " << endl;
     // NOTE: invoked passed by reference, can simply pass the ordinary constants
     // herein may be combined function parameters, & a = a, so that here only write A 
    refSwap (A, B);
    cout << "a:" << a << endl;
    cout << "b:" << b << endl;


    COUT << " pointer exchange: " << endl;
     // NOTE: When invoked with a pointer, and needs &
     // herein may be combined with the function parameter, * a = & a, so there need to take the write address & 
    pointSwap (& A, & B) ;
    cout << "a:" << a << endl;
    cout << "b:" << b << endl;

    cout << "end." << endl;
    return 0;
}

Output is as follows: