是否有一种方法可以在运行时停止循环重复一次不止一次

Question

我想构建一个简单的问卷程序。当我运行代码时，当我只想运行一次并且不重复Cout语句时，它将两次重复该语句。仅当我使用字符串而不是字符时，才会发生。对不起笨拙的写作。[在此处输入图像说明] [1]

代码如下：

#include<iostream>
#include<string>
using namespace std;
bool N='n';
bool Y='y';
bool YES="yes";
bool NO="no";
int main(){
    char response, response2, response3;
    string response_1, response_2, response_3;

    cout<<"Hello would you like to answer a few questions?"<<endl<<"Please input y or n"<<endl;
    cin>>response;
    {  do{
        if((response_1=="yes")||(response=='y')){
        cout<<"please continue:"<<endl;
        break;}
    else if((response_1=="no")||(response=='n')){
        cout<<"Please exit the program then:"<<endl;
        }
    else{
        cout<<"Wrong input";
    }
}
    while((response_1!="yes")||(response!='y'));
}
    { do{
    cout<<"Question one"<<endl<<"Can birds sing?.....";/*This statement repeats more than once.*/
    cin>>response2;
    if((response_2=="yes")||(response2=='y')){
        cout<<"Correct they do sing"<<endl;
        break;
    }
    else if((response_2=="no")||(response2=='n')){
        cout<<"Do you want to try again?"<<endl;
    }
    else{
}
}
    while((response_2!="yes")||(response2!='y'));
}
  { do{
    cout<<"Question two now"<<endl<<"Are pigs smart?......"<<endl;/*This on also repeats moer than once*/
    cin>>response3;
    if((response_3=="yes")||(response3=='y')){
        cout<<"Yes they are smart"<<endl;
        break;
    }
    else if((response_3=="no")||(response3=='n')){
        cout<<"Do you want to try again?"<<endl;
    }
    else{
    }
}
    while((response_3!="yes")||(response3!='y'));
}
    return 0;
}

[1]: https://i.stack.imgur.com/bTnBY.jpg

Answer 1

您将response声明为char，但第一次试图从控制台初始化它

cin>>response;

您的输入包含3个字符(在您的第三行中"是" [1](，因此response获取'y'，但是" e"one_answers" e"one_answers" s"现在也在输入流中，所以这是原因，为什么在控制台的下一次阅读中：

cin>>response2;

response2用" e"初始化，这会导致额外的 Can birds sing?.....Question one打印，然后'reverse 2'get's'并再次打印额外的线。

我建议您删除所有冗余变量，并仅使用STD :: String response。然后很难犯错。

Answer 2

您可以添加一个变量，该变量计算循环已循环

int loopCount = 0;
int LoopMaxTries = 1;
while ( loopCount < LoopMaxTries /* and possibly other stuff */ ) {
    // at the end of the loop
    loopCount++;
}