输入任意数量双精度数存入容器并对双精度数容器内的数求和

#include<iostream>
#include<vector>
#include<cstdlib>
using std::vector;
using std::cin;
using std::cout;
using std::istream;

vector<double> a1;

double sum1(vector<double>::iterator t1,vector<double>::iterator t2);
double sum2(vector<double>& vecc);


int main()
{
    double tmp_lon;
    char test_state;
    cin.unsetf(istream::skipws);
    while (cin&&cin>>tmp_lon)
    {
        cin>>test_state;
        if (test_state=='cr'||test_state=='\n') cin.setstate(istream::eofbit);
        a1.push_back(tmp_lon);
    }

 

 

    if (a1.begin()==a1.end()) cout<< 0 <<std::endl;
    else
    {
        vector<double>::iterator iter1=a1.begin(),iter2=a1.end();

        cout<<std::endl<<sum1(iter1,iter2)<<std::endl;
        cout<<sum2(a1)<<std::endl;
    }
    system("pause");
    return 0;
}
double sum1(vector<double>::iterator t1,vector<double>::iterator t2)
{
    double tm_sum=0;
    while (t1!=t2)
    {
        tm_sum+=*t1;
        ++t1;
    }
    return tm_sum;
}

double sum2(vector<double>& vecc)
{
    vector<double>::iterator tmp_iter=vecc.begin();
    double tmp_sum=0;
    while (tmp_iter!=vecc.end())
    {
        tmp_sum+=*tmp_iter;
        ++tmp_iter;
    }
    return tmp_sum;
}