没看懂，帮我看看吧
这是以前的帖子中关于max和min函数的回复，有的地方不懂
Summary
Finds and returns the maximum of a pair of values.
Synopsis
#include <algorithm>
template <class T>
const T& max(const T&, const T&);
template <class T, class Compare>
const T& max(const T&, const T&, Compare);
Description
The max algorithm determines and returns the maximum of a pair of values. The optional argument Compare defines a comparison function that can be used in place of the default operator<.
max returns the first argument when the arguments are equal.
Example
//
// max.cpp
//
#include <algorithm>
#include <iostream>
#include <functional>
using namespace std;
int main(void)
{
double d1 = 10.0, d2 = 20.0;
// Find minimum
double val1 = min(d1, d2);
// val1 = 10.0
这里不明白，为啥min函数要返回最大值呢
// the greater comparator returns the greater of the
// two values.
double val2 = min(d1, d2, greater<double>());
// val2 = 20.0;
// Find maximum
double val3 = max(d1, d2);
// val3 = 20.0;
// the less comparator returns the smaller of
// the two values.
// Note that, like every comparison in the STL, max is
// defined in terms of the < operator, so using less here
// is the same as using the max algorithm with a default
// comparator.
这里为啥还是返回最大值呢
double val4 = max(d1, d2, less<double>());
// val4 = 20
cout << val1 << " " << val2 << " "
<< val3 << " " << val4 << endl;
return 0;
}
Program Output
10 20 20 20
See Also
max_element, min, min_element
问题点数：20、回复次数：1Top
1 楼xkit（乌普）回复于 2005-06-01 20:32:33 得分 20
stl中 less 和 max 的实现
template <class _Tp>
struct less : public binary_function<_Tp,_Tp,bool>
{
bool operator()(const _Tp& __x, const _Tp& __y) const { return __x < __y; }
};
template <class _Tp, class _Compare>
inline const _Tp& (max)(const _Tp& __a, const _Tp& __b, _Compare __comp) {
return __comp(__a, __b) ? __b : __a;
}
template <class _Tp>
inline const _Tp& (max)(const _Tp& __a, const _Tp& __b) { return __a < __b ? __b : __a; }
若用less 则max(d1,d2)和max(d1,d2,less<double>())中d1,d2进行相同的比较,若用greater可以得到最小值Top
