一行输入多个数字 [英] multiple numbers input on one line

问题描述

我想知道如何在一行中接受多个数字，而不必事先确切知道有多少个数字.

I want to know how I can accept multiple numbers on one line without exactly knowing in advance how many.

例如，如果我输入1 2 3 4，则可以使用:

So for example if I have 1 2 3 4 as input I could use :

cin >> a >> b >> c >> d;

但是，如果我不知道数量是4，那么我将无法使用该方法.将输入存储到向量中的正确方法是什么?

But if I don't know that the amount is 4 then I can't use that approach. What would be the right way to store the input into a vector?

预先感谢

推荐答案

您可以读取所有输入，直到在std :: string类型的对象中换行符为止，然后从该字符串中提取数字并将其放置在例如向量.

You can read all input until the new line character in an object of type std::string and then extract numbers from this string and place them for example in a vector.

这是一个随时可以使用的示例

Here is a ready to use example

#include <iostream>
#include <sstream>
#include <iterator>
#include <string>
#include <vector>

int main() 
{
    std::string s;

    std::getline( std::cin, s );

    std::istringstream is( s );

    std::vector<int> v( ( std::istream_iterator<int>( is ) ), std::istream_iterator<int>() );

    for ( int x : v) std::cout << x << ' ';
    std::cout << std::endl;

    return 0;
}

如果您要输入一行数字

1 2 3 4 5 6 7 8 9 

那么矢量的程序输出将是

then the program output from the vector will be

1 2 3 4 5 6 7 8 9 

在此程序中，您可以替换语句

In this program you could substitute statement

std::vector<int> v( ( std::istream_iterator<int>( is ) ), std::istream_iterator<int>() );

为

std::vector<int> v;
int x;

while ( is >> x ) v.push_back( x );

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