Question

我想构建一个简单的问卷调查程序。当我运行代码时，如果我只希望运行一次而不重复cout语句，它将重复两次该语句。这仅在我使用字符串而不是字符时发生。对不起，我的写作很笨拙。[在此处输入图片描述] [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声明为字符，但这是您首次尝试从控制台对其进行初始化时

cin>>response;

您的输入包含3个字符（示例[1]第三行中的“是”），因此response得到'y'，但是'e'和's'现在也在输入流中，所以这就是为什么在下一次从控制台读取时的原因：

cin>>response2;

response2用'e'初始化，这会导致打印额外的Can birds sing?.....Question one，然后'response2'得到's'并再次打印多余的行。

我建议您删除所有冗余变量，并仅使用std :: string response。那样会容易出错。

Answer 2

您可以添加一个变量，该变量计算循环循环的次数

+--------------+----------------+-----------+
| usps_primary | usps_preferred | variation |
+--------------+----------------+-----------+
| ALLEY        | ALY            | ALLEY     |
| ALLEY        | ALY            | ALLEE     |
| ALLEY        | ALY            | ALLY      |
| ALLEY        | ALY            | ALY       |
| ANEX         | ANX            | ANX       |
| ANEX         | ANX            | ANNX      |
| ANEX         | ANX            | ANEX      |
| ANEX         | ANX            | ANNEX     |
| East         | E              | E         |
| East         | E              | East      |
| North        | N              | North     |
| North        | N              | N         |
| South        | S              | South     |
| South        | S              | S         |
| West         | W              | W         |
| West         | W              | West      |
+--------------+----------------+-----------+

有没有一种方法可以使循环在运行时不止一次重复

2 个答案: