用户输入整数 - 错误处理

Question

我在程序的某些输入区域遇到了一些麻烦.用户输入特定整数的部分内容.即使他们输入了一个非常精细和花花公子的错误,但我注意到如果他们输入的内容不是像'm'这样的整数类型,那么它将重复循环错误消息.

我有几个函数,其中包含整数输入.这是一个例子.

void Room::move(vector<Room>& v, int exone, int extwo, int exthree, int current)
{
    v[current].is_occupied = false;
    int room_choice;
    cout << "\nEnter room to move to: ";
    while(true)
    {
        cin >> room_choice;
        if(room_choice == exone || room_choice == extwo || room_choice == exthree)
        {
            v[room_choice].is_occupied = true;
            break;
        }
        else cout << "Incorrect entry. Try again: ";
    }
}

[解决了]

void Room::move(vector<Room>& v, int exone, int extwo, int exthree, int current)
{
    v[current].is_occupied = false;
    int room_choice;
    cout << "\nEnter room to move to: ";
    while(true)
    {
        cin >> room_choice;
        if(room_choice == exone || room_choice == extwo || room_choice == exthree)
        {
            v[room_choice].is_occupied = true;
            break;
        }
        else cout << "Incorrect entry. Try again: ";
    }
}

Answer 1

您的"已解决"代码中仍然存在问题.您应该在检查值之前检查fail().(显然,与格式问题相反,存在eof()和IO故障的问题).

习惯性的阅读是

if (cin >> choice) {
   // read succeeded
} else if (cin.bad()) {
   // IO error
} else if (cin.eof()) {
   // EOF reached (perhaps combined with a format problem)
} else {
   // format problem
}

Answer 2

您可以使用cin.good()或cin.fail()确定cin是否可以成功处理提供的输入值.cin.clear()如有必要,您可以在继续处理之前使用它来清除错误状态.