ex6_01.cpp

Beginning Visual C++ 6源码。Wrox。

// EX6_01.CPP
// Exercising pointers to functions
#include <iostream>
using namespace std;

long sum(long a, long b);            // Function prototype
long product(long a, long b);        // Function prototype

int main(void)
{
   long (*pdo_it)(long, long);       // Pointer to function declaration

   pdo_it = product;
   cout << endl
        << "3*5 = " << pdo_it(3, 5); // Call product thru a pointer

   pdo_it = sum;                     // Reassign pointer to sum()
   cout << endl
        << "3*(4+5) + 6 = " 
        << pdo_it(product(3, pdo_it(4, 5)), 6); // Call thru a pointer
                                                // twice
   cout << endl;
   return 0;
}

// Function to multiply two values
long product(long a, long b)
{
   return a*b;
}

// Function to add two values
long sum(long a, long b)
{
   return a+b;
}