Question

我试图提示用户输入他或她的名字。我写了＃34; hello，first_name＆＃34;，其中first_name是用户输入的名称。然后我按如下方式修改了代码：将提示更改为＆＃34;输入要写入的人的姓名＆＃34;并将输出更改为＆＃34;你好，first_name，＆＃34;你喜欢你现在生活中的哪个地方（y / n）？＆＃34 ;; 这是在我写一个if语句之前，让用户决定要执行什么代码，但是在给定的条件下输入＆＃34;条件＆＃34;我没有工作，因为它没有定义，尽管我把它们分配给了＆＃39; y＆＃39;并且＆＃39; n＆＃39;。简而言之，我完全不了解如何定义first_name和输入，我试图让用户输入要分配给这些变量的值。 The Error list

 #include "stdafx.h"
 #include "iostream"
 #include"string"
 using namespace std;

 int main()
     {
string first_name;
cout << " Please enter your first name (followed by 'enter'):\n";
cin >> first_name;
    cout << "Hello," << first_name << " do you like where you are right now in life (y/n)?:\n";
    cin >> first_name;
    if (input =='y') {
        cout << "what do you like about it over,the people?(y/n)";//?:\n"

    }
    else if (input == 'n') {
        cout << " what do you hate about it,the expenses?(y/n)"//?:\n"
    }
    else cout << "invalid choice";
    cout << " what was your friends name again ?" << endl;
    string = friends_name;
    cin >> friends_name;
}
return 0;
     }
   }

Answer 1

在你的程序的第12行，看起来你已经使用变量first_name而不是输入。将“first_name”替换为“input”。例如：

cin>>input

同样如评论中所述，请确保声明您使用的所有变量

例如：

string first_name;
string input;
string friends_name;

编辑的工作代码如下：

 #include "stdafx.h"
 #include "iostream"
 #include"string"
 using namespace std;

int main(){
 string first_name;
 string friends_name;
 string input;
 cout << " Please enter your first name (followed by 'enter'):\n";
 cin >> first_name;
 cout << "Hello," << first_name << " do you like where you are right now in life (y/n)?:\n";
 cin >> input;
 if (input =="y")
     cout << "what do you like about it over,the people?(y/n)";//?:\n"
 else if (input == "n")
    cout << " what do you hate about it,the expenses?(y/n)";//?:\n"
 else cout << "invalid choice";
 cout << " what was your friends name again ?" << endl;
 cin >> friends_name;
 return 0;
 }

标识符＆＃34; friends_name＆＃34;未定义＆amp;标识符＆＃34;输入＆＃34;未定义？ C ++

1 个答案: