c ++ cin输入不工作？ [英] c++ cin input not working?

问题描述

  #include< iostream> 
 #include< string> 
 
 struct Car {
 std :: string model; 
 unsigned int year; 
}; 
 
 int main（）{
 using namespace std; 
 
 int carNum; 
 cout<< 你想要多少辆汽车？; 
 cin>> carNum; 
 Car * cars = new Car [carNum]; 
 
 for（int i = 0; i  cout< Car＃<< i<< endl; 
 cout<< 请输入make：; 
 getline（cin，cars [i] .model）; 
 
 cout<< 请输入年份：; 
 cars [i] .year = cin.get（）; 
} 
 
 cout<< 这里是您的收藏< endl; 
 
 for（int i = 0; i  cout<汽车[i] .model< <汽车[i] .year< endl; 
} 
 
 delete [] cars; 
 
 return 0; 
} 
  

当我执行程序时， getline ，car [i] .model）刚刚跳过。为什么呢？

像这样：

  Car＃2 
请输入make：请输入年份：
  

解决方案

简单的原因。

cin>无论，都会留下一个 \\\
（按下Enter时添加）。默认情况下， getline 读取到下一个 \\\
，因此下一个读取将只读取一个空字符串。 / p>

解决方法是舍弃 \\\
。您可以执行此操作：

  cin.ignore（numeric_limits< streamsize> :: max（），'\\\
 '）; 
  

刚刚在 cin>





不要忘记包含 limits c $ c> numeric_limits 。

#include <iostream>
#include <string>

struct Car{
    std::string model;
    unsigned int year;
};

int main(){
    using namespace std;

    int carNum;
    cout << "How many cars do you wish you catalog? ";
    cin >> carNum;
    Car * cars = new Car[carNum];

    for (int i=0;i<carNum;i++){
        cout << "Car #" << i << endl;
        cout << "Please enter the make: ";
        getline(cin, cars[i].model);

        cout << "Please enter the year made: ";
        cars[i].year = cin.get();
    }

    cout << "Here's your collection" << endl;

    for (int i=0;i<carNum;i++){
        cout << cars[i].model << " " << cars[i].year << endl;
    }

    delete [] cars;

    return 0;
}

When i execute the program, the getline(cin, car[i].model) just get skipped over. Why is this?

like this:

Car #2
Please enter the make: Please enter the year made:

解决方案

Simple reason.

When you do cin >> whatever, a \n is left behind (it was added when you pressed Enter). By default, getline reads until the next \n, so the next read will simply read an empty string.

The solution is to discard that \n. You can do it by putting this:

cin.ignore(numeric_limits<streamsize>::max(),'\n');

Just after the cin >> carNum.

Don't forget to include limits in order to use numeric_limits.

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