/* function that compares two pointers by comparing the values to which they point
 */
bool int_ptr_less (int* a, int* b)
{
    return *a < *b;
}

int main()
{
    int x = 17;
    int y = 42;
    int* px = &x;
    int* py = &y;
    int* pmax;

    // call max() with special comparison function
    pmax = max (px, py, int_ptr_less);
    //...
}
这是源代码(MSVC7):
template<class _Ty,
 class _Pr> inline
 const _Ty& _MAX(const _Ty& _Left, const _Ty& _Right, _Pr _Pred)
 { // return larger of _Left and _Right using _Pred
 return (_Pred(_Left, _Right) ? _Right : _Left);
 }

2.设置boolalpha可以让流输出bool值的字符串形式

 cout << boolalpha ;
 bool b = true;
 cout << b <<"*********"<<!b << endl;
结果:
true*********false
3。一下代码可以测试你的系统各类型的范围
#include <iostream>
#include <limits>
#include <string>
using namespace std;

int main()
{
   // use textual representation for bool
   cout << boolalpha;

   // print maximum of integral types
   cout << "max(short): " << numeric_limits<short>::max() << endl;
   cout << "max(int):   " << numeric_limits<int>::max() << endl;
   cout << "max(long):  " << numeric_limits<long>::max() << endl;
   cout << endl;

   // print maximum of floating-point types
   cout << "max(float):       "
        << numeric_limits<float>::max() << endl;
   cout << "max(double):      "
        << numeric_limits<double>::max() << endl;
   cout << "max(long double): "
        << numeric_limits<long double>::max() << endl;
   cout << endl;

   // print whether char is signed
   cout << "is_signed(char): "
        << numeric_limits<char>::is_signed << endl;
   cout << endl;

   // print whether numeric limits for type string exist
   cout << "is_specialized(string): "
        << numeric_limits<string>::is_specialized << endl;
}