replaceif.cpp

/*
   Demonstration of the replace_if algorithm.
   This program also shows how an ostream_iterator can be used with
   the copy algorithm to copy the contents of a vector to cout.
   NDE, 2014-01-07
*/
#include <vector>
#include <iterator>
#include <iostream>
#include <algorithm>
using namespace std;
bool is_negative(int value)
{
  return value < 0;
}
int main()
{
  // Populate a vector with some integers
  vector<int> v;
  for (int i = -5; i <= 5; ++i) {
    v.push_back(i);
  }
  // Display vector contents
  ostream_iterator<int> out(cout, " ");
  cout << "Before: ";
  copy(v.begin(), v.end(), out);
  cout << endl;
  // Replace negative values with zero
  replace_if(v.begin(), v.end(), is_negative, 0);
  // Display vector contents again
  cout << "After: ";
  copy(v.begin(), v.end(), out);
  cout << endl;
  return 0;
}