c++代码

#include<iostream>

using namespace std;

int main()
{
    string s1,s2;
    getline(cin, s1);

    int cnt = 0;
    int flag = 1;
    for(int i = 0; s1[i]; i ++ )
    {
        if(s1[i] != ' ') {
            s2 += s1[i];
            flag = 1;
        }else{
            if(flag) s2 += ' ';
            flag = 0;
        }
    }

    cout << s2 << endl;

    return 0;
}