我怎样才能在同一行得到我程序的所有总和？

Question

我试图在程序结束时将所有输出打印在一行上。我怎样才能做到这一点？目前，输入变量后直接打印总和，看起来像这样：

我希望它看起来像这样：

3
100 8
15 245
1945 54

108 260 1999

这是我目前的代码：

#include <iostream>
using namespace std;

int main()
{
    int pairs = 0;
    cin >> pairs;

    for (int i=0,num1=0,num2=0; i < pairs; i++)
    {
        cin >> num1 >> num2;
        cout << num1 + num2 << " ";
    }
}

Answer 1

起初，我不清楚你在问什么，但我明白了。您正在同一个循环中进行输入和输出。您需要有一个输入和输出循环以及一个容器：

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

int main()
{
    int pairs = 0;
    cin >> pairs;
    std::vector<int> sums; // vector to hold sums, your int sum was unused
    sums.reserve(pairs);

    for(int i = 0; i < pairs; ++i)
    {
        // better initialize these variables here, otherwise they might
        // equal to previous input if this input fails
        // (you should declare them in inner-most scope possible anyway)
        int num1 = 0, num2 = 0;
        cin >> num1 >> num2;
        sums.push_back(num1 + num2); // do not cout, append the value to the sums instead
    }

    for(auto x : sums)
        cout << x << " "; // finally print the whole vector
}

Answer 2

只是为了提供一个方便的替代方案：您可以将输出发送到一个 std::ostringstream 变量，直到您想要使用它...

#include <iostream>
#include <sstream>

int main()
{
    int pairs;
    if (std::cin >> pairs)
    {
       std::ostringstream saved_out;

       for (int i = 0; i < pairs; ++i)
       {
           int num1, num2;
           if (std::cin >> num1 >> num2)
               saved_out << num1 + num2 << " ";
           else
           {
               std::cerr << "ERROR: less inputs than promised\n";
               exit(1);
           }
        }
    }
    else
    {
        std::cerr << "unable to parse pairs counter from stdin\n";
        exit(1);
    }
    std::cout << saved_out.str() << '\n';
}

我还对输入进行了更多检查robust/verbose。

我怎样才能在同一行得到我程序的所有总和？

How could I get all of the sums of my program on the same line?

c++

io