c++ max_elment和min_element

  max_element和min_element用来求一个范围内的最大值和最小值

template <class ForwardIterator>
  ForwardIterator max_element ( ForwardIterator first, ForwardIterator last );

template <class ForwardIterator, class Compare>
  ForwardIterator max_element ( ForwardIterator first, ForwardIterator last,
                                Compare comp );

int max= *max_element(v.begin(),v.end());  //注意返回的是一个迭代器，*取值

  int max= *min_element(energy.begin(),energy.end());  //求最小值

// min_element/max_element
#include <iostream>
#include <algorithm>
using namespace std;

bool myfn(int i, int j) { return i<j; }

struct myclass {
  bool operator() (int i,int j) { return i<j; }
} myobj;

int main () {
  int myints[] = {3,7,2,5,6,4,9};

  // using default comparison:
  cout << "The smallest element is " << *min_element(myints,myints+7) << endl;
  cout << "The largest element is " << *max_element(myints,myints+7) << endl;

  // using function myfn as comp:
  cout << "The smallest element is " << *min_element(myints,myints+7,myfn) << endl;
  cout << "The largest element is " << *max_element(myints,myints+7,myfn) << endl;

  // using object myobj as comp:
  cout << "The smallest element is " << *min_element(myints,myints+7,myobj) << endl;
  cout << "The largest element is " << *max_element(myints,myints+7,myobj) << endl;

  return 0;
}

The example illustrates how the comparison object can be either a function or an object whose class defines theoperator() member. In this case both have been defined to perform a standard less-than comparison.
Output:

The smallest element is 2
The largest element is 9