5.3.5.2 packaged_task

#include<iostream>
#include<future>
#include<thread>
#include<vector>
#include<numeric>  //accumulate
using namespace std;
double accum(double* beg,double* end,double init){
    return accumulate(beg,end,init);
}
double comp2(vector<double>&v){
    using Task_type=double(double*,double*,double);
    packaged_task<Task_type> pt0{accum};
    packaged_task<Task_type> pt1{accum};
    future<double> f0{pt0.get_future()};
    future<double> f1{pt1.get_future()};  
    double* first=&v[0];
    thread t0{move(pt0),first,first+v.size()/2,0};
    thread t1{move(pt1),first+v.size()/2,first+v.size(),0};
    t0.join();
    t1.join();
    return f0.get()+f1.get();
}
int main(){
    vector<double> vd{1,2,3,4,5,6,7};
    cout<<comp2(vd)<<endl;
    system("pause");
    return 0;
}

运行结果

PS D:\Codes\test> g++ test.cpp
PS D:\Codes\test> ./a.exe     
28
请按任意键继续. . .