ex6_02.cpp

Wrox.Ivor.Hortons.Beginning.Visual.C.Plus.Plus.2008 With sourcecode

// Ex6_02.cpp
// A pointer to a function as an argument
#include <iostream>
using std::cout;
using std::endl;

// 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;
}