cin.getline不會讓用戶輸入值

Question

可能重複：
cin.getline() is skipping an input in C++

我工作的C++，拿到2部電影像一些數據以下：

struct Movie m1, m2; 
    cout << "Enter first movie title: "; 
    cin.getline(m1.title, 30); 
    cout << "Enter first movie director: "; 
    cin.getline(m1.director, 30); 
    cout << "Enter first movie length: "; 
    cin >> m1.length; 

    cout << "Enter second movie title: "; 
    cin.getline(m2.title, 30); 
    cout << "Enter second movie director: "; 
    cin.getline(m2.director, 30); 
    cout << "Enter second movie length: "; 
    cin >> m2.length; 

但是，我很驚訝，在輸出它並不是所有我輸入第二部電影的標題。下面是輸出

Enter first movie title: Girl 

Enter first movie director: GirlD 

Enter first movie length: 10 

Enter second movie title: Enter second movie director: Boy 

Enter second movie length: 20 

Answer 1

的cin >> m1.length;，其唯一的閱讀次數，所以給人們留下了\n，接下來的函數getline將讀取的空行，所以你可以把它讀作這樣的：

string temp; 
cin.getline(temp, 30); 
stringstream sst(temp); 
sst >> m1.lenght;