1.每次读入一个单词

#include<iostream>
#include<string>
using namespace std;
int main(){
    string word;
    int n=1;
    while(cin>>word){
        cout<<n<<": "<<word<<endl;
        n++;
    }
    cout<<endl;
    system("pause");
    return 0;
}

2.每次读入一行文本

#include<iostream>
#include<string>
using namespace std;
int main(){
    string line;
    int n=1;
    while(getline(cin,line)){
        cout<<n<<": "<<line<<endl;
        n++;
    }
    cout<<endl;
    system("pause");
    return 0;
}