istringstream

#include <iostream>
#include <sstream>
#include<fstream>
#include<vector>
#include<string>
using namespace std;

int main()
{
    ifstream input("1.txt");
    string line;
    vector<string> vec;
    string tmp;
    while(getline(input,line))
    {
        vec.push_back(line);
    }
    for(auto v:vec)
    {
        cout<<v<<endl;
        istringstream istr(v);
        //打印一行字符串v
        cout<<istr.str()<<endl;
        //打印每个单词
        while(istr>>tmp)
            cout<<tmp<<endl;
    }
    return 0;
}