algorithm与numeric的一些常用函数

numeric中的accumulated的基本用法：

来自：https://blog.csdn.net/u011499425/article/details/52756242

 #include <vector>
 #include<numeric>
 #include<iostream>
 #include <string>
 using namespace std;
 struct Grade
 {
     string name;
     int grade;
 };
 int cmp(int a, Grade b)
 {
     return a + b.grade;
 }
 int main()
 {
     Grade subject[] = {
         { "English",  },
     { "Biology",  },
     { "History",  }
     };

     //int sum = accumulate(subject, subject + 3, 0, [](int a, Grade b) {return a + b.grade; });
     int sum = accumulate(subject, subject + , , cmp);
     cout << sum << endl;

     system("pause");
     return ;
 }

algorithm的count:利用等于操作符，把标志范围内的元素与输入值比较，返回相等元素个数。

#include<iostream>
#include<algorithm>
using namespace std;
int main()
{
    int a[] = { , , ,  };
    int k = count(a, a + ,);
    cout << k << endl;
    return ;
}

unique:去重；