Accumulate(累積) values in range

accumulate帶有三個形參：頭兩個形參指定要累加的元素範圍，第三個形參則是累加的初值。

模板：

template <class InputIterator, class T>
   T accumulate (InputIterator first, InputIterator last, T init)
{
  while (first!=last) {
    init = init + *first;  // or: init=binary_op(init,*first) for the binary_op version
    ++first;
  }
  return init;
}
 

#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
using namespace std;

int main()
{
    vector<int> num={1,2,3,4,5,6,7,8,9,10};
    vector<string> str={"1","2","3","4","5"};
    int sum = accumulate(num.begin(),num.end(),0);
    string sum1 = accumulate(str.begin(),str.end(),string(""));
    cout <<sum<< endl;   //55
    cout <<sum1<<endl;   //12345
    return 0;
}