How to read a single line of numbers into different variables? [closed]

问题

Program looks like:

#include <iostream>
#include <string>

using namespace std;

int main()
{
    //Code

    int num1, num2, num3, num4, num5, num6;


    int num[6] = { num1, num2, num3, num4, num5, num6 };

    cout << "Enter one line containing at least 6 integers." << endl;

    getline(cin, num);

Line of input: 1 2 87 1 2 123 44

And I need to store each number into variables Num1, Num2, Num3, etc.

回答1:

From your output message, it seems like you're expecting at least 6 integers as input. That means you want a container that you can add an arbitrary number of elements to, like std::vector<int> Nums;. You can then use std::copy to extract ints from cin and push them into the vector with a std::back_inserter:

std::copy(std::istream_iterator<int>(std::cin),
          std::istream_iterator<int>(),
          std::back_inserter(Nums));

See it in action.

There may be a reasonable number of things here that you're not familiar with:

std::copy is an algorithm that copies from one range to another range. The first two arguments denote the beginning and end of the range to copy from, and the third argument denotes the beginning of the range to copy to.
std::istream_iterator is an iterator type that extracts from the stream you give it when it is incremented.
std::istream_iterator<int>(std::cin) constructs an iterator that will extract ints from std::cin
std::istream_iterator<int>() constructs a special end-of-stream iterator. It represents the end of any arbitrary stream. This means that the copy algorithm will stop when it reaches the end of the stream.
std::back_inserter creates another iterator that calls push_back on the container you give it every time it is assigned to. As the copy algorithm will assign to this iterator the ints extracted from the stream, it will push them all into the vector Nums.

If that's too complicated, here's another version that uses less library components:

int val;
while (std::cin >> val) {
  Nums.push_back(val);
}

来源：https://stackoverflow.com/questions/21614999/how-to-read-a-single-line-of-numbers-into-different-variables

标签

c++

xcode

variables

cin