accumulate的用法

#include <iostream>#include <vector>#include <string>#include <numeric>#include <functional>#include <algorithm>using namespace std;string::size_type stringLengthSum(string::size_type SumSoFar,const string& s){return SumSoFar+s.size();}int main(){vector<string> vec;vec.push_back("a");vec.push_back("bc");vec.push_back("dfe");vec.push_back("ghij");string::size_type lengthSum=accumulate(vec.begin(),vec.end(),static_cast<string::size_type>(0),stringLengthSum);cout<<lengthSum<<endl;vector<float> vec1;vec1.push_back(1.0);vec1.push_back(2.0);vec1.push_back(3.0);vec1.push_back(4.0);vec1.push_back(5.0);float product=accumulate(vec1.begin(),vec1.end(),1.0f,multiplies<float>());cout<<product<<endl;return 0;}