randgentest.cpp

Thingking in c++第二版

//: C05:RandGenTest.cpp
// From Thinking in C++, 2nd Edition
// Available at http://www.BruceEckel.com
// (c) Bruce Eckel 2000
// Copyright notice in Copyright.txt
// A little test of the random number generator
#include <algorithm>
#include <vector>
#include <iostream>
#include <functional>
#include <cstdlib>
#include <ctime>
using namespace std;

int main() {
  const int sz = 10000;
  int v[sz];
  srand(time(0)); // Seed the random generator
  for(int i = 0; i < 300; i++) {
    // Using a naked pointer to function:
    generate(v, v + sz, std::rand);
    int count = count_if(v, v + sz, 
      bind2nd(greater<int>(), RAND_MAX/2));
    cout << (((double)count)/((double)sz)) * 100
      << ' ';
  }
} ///:~