ex6_02.cpp

来自「Beginning Visual C++ 6源码。Wrox。」· C++ 代码 · 共 50 行

//EX6_02.CPP
// A pointer to a function as an argument
#include <iostream>
using namespace std;

// Function prototypes
double squared(double);
double cubed(double);
double sumarray(double array[], int len, double (*pfun)(double));

int main(void)
{
   double array[] = { 1.5, 2.5, 3.5, 4.5, 5.5, 6.5, 7.5 };
   int len = sizeof array/sizeof array[0];

   cout << endl
        << "Sum of squares = "
        << sumarray(array,len,squared);

   cout << endl
        << "Sum of cubes = "
        << sumarray(array,len,cubed);

   cout << endl;
   return 0;
}

// Function for a square of a value
double squared(double x)
{
   return x*x;
}

// Function for a cube of a value
double cubed(double x)
{
   return x*x*x;
}

// Function to sum functions of array elements
double sumarray(double array[], int len, double (*pfun)(double))
{
   double total = 0.0;     // Accumulate total in here

   for(int i=0; i<len; i++)
      total += pfun(array[i]);

   return total;
}