为什么是这样
#include<iostream>
#include<string>
using namespace std;

int main()
{
int secondpos,thirdpos;
string sentence,str;
const string str1="and";

cout<<"input the sentence: ";
getline(cin,sentence);
str=sentence.substr(sentence.find(str1)+3,1000);
secondpos=str.find(str1)+sentence.find(str1)+3;
cout<<"the second position of \"and\" is "<<secondpos<<endl;

str=sentence.substr(secondpos+3,1000);
thirdpos=secondpos+str.find(str1)+3;
cout<<"the third position of \"and\" is "<<thirdpos<<endl;
return 0;
}
为什么这段代码要按两次Enter键才出来结果？

[解决办法]
一下Enter就够了。不过如一楼所说，程序会有问题