(const unsigned int n);
 
int main()
{
  srandom( time(NULL) );  // Seed random generator
  Display(v, "Before shuffle:");
 
  pointer_to_unary_function<unsigned int, unsigned int>
    ptr_RandInt = ptr_fun(RandInt);  // Pointer to RandInt()//注意这行
  random_shuffle(v.begin(), v.end(), ptr_RandInt);
 
  Display(v, "After shuffle:");
  return 0;
}
 
// Display contents of vector vr
void Display(vector<int>& vr, const char *s)
{
  cout << endl << s << endl;
  copy(vr.begin(), vr.end(), ostream_iterator<int>(cout, " "));
  cout << endl;
}
 
 
// Return next random value in sequence modulo n
unsigned int RandInt(const unsigned int n)
{
  return random() % n;
}
编译运行结果如下：

$ g++ randfunc.cpp
$ ./a.out
Before shuffle:
1 2 3 4 5 6 7 8 9 10
After shuffle:
6 7 2 8 3 5 10 1 9 4
首先用下面的语句申明一个对象：

pointer_to_unary_function<unsigned int, unsigned int>
  ptr_RandInt = ptr_fun(RandInt);
这儿使用STL的单目函数模板定义了一个变量ptr_RandInt，并将地址初始化到我们的函数RandInt()。单目函数接受一个参数，并返回一个值。现在random_shuffle()可以如下调用：

random_shuffle(v.begin(), v.end(), ptr_RandInt);
在本例子中，发生器只是简单的调用rand()函数。
 
关于常量引用的一点小麻烦（不翻译了，VC下将例子中的const去掉）

发生器函数类对象
下面的例子说明发生器函数类对象的使用。

Listing 10. fiborand.cpp

#include <iostream.h>
#include <algorithm>   // Need random_shuffle()
#include <vector>      // Need vector
#include <functional>  // Need unary_function
 
using namespace std;
 
// Data to randomize
int iarray = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
vector<int> v(iarray, iarray + 10);
 
// Function prototype
void Display(vector<int>& vr, const char *s);
 
// The FiboRand template function-object class
template <class Arg>
class FiboRand : public unary_function<Arg, Arg> {
  int i, j;
  Arg sequence[18];
public:
  FiboRand();
  Arg operator()(const Arg& arg);
};
 
void main()
{
  FiboRand<int> fibogen;  // Construct generator object
  cout << "Fibonacci random number generator" << endl;
  cout << "using random_shuffle and a function object" << endl;
  Display(v, "Before shuffle:");
  random_shuffle(v.begin(), v.end(), fibogen);
  Display(v, "After shuffle:");
}
 
// Display contents of vector vr
void Display(vector<int>& vr, const char *s)
{
  cout << endl << s << endl;
  copy(vr.begin(), vr.end(),
    ostream_iterator<int>(cout, " "));
  cout << endl;
}
 
// FiboRand class constructor
template<class Arg>
FiboRand<Arg>::FiboRand()
{
  sequence[17] = 1;
  sequence[16] = 2;
  for (int n = 15; n > 0; n—)
    sequence[n] = sequence[n + 1] + sequence[n + 2];
  i = 17;
  j