循环不正常

Question

我正在制作一个名叫吉尔伯特的机器人,他充满了愚蠢.到目前为止.

http://pastecode.org/index.php/view/36572371

让我们说他回答了一个问题,然后就会说

"问别人？(是/否)"

如果我说Y,它会说

"问别人？(是/否)"

再次.说Y再问你一次.我该如何解决？

//  Created by Brad Gainsburg on 4/23/13.
//  Copyright (c) 2013 Ostrich. All rights reserved.

#include <iostream>
#include <string>

using namespace std;

int main(int argc, const char* argv[]) {
    cout << "   _____ _ _ _              _   " << endl;
    cout << " / ____(_) | |             | |  " << endl;
    cout << "| |  __ _| | |__   ___ _ __| |_ " << endl;
    cout << "| | |_ | | | '_ \\ / _ \\ '__| __|" << endl;
    cout << "| |__| | | | |_) |  __/ |  | |_ " << endl;
    cout << " \\_____|_|_|_.__/ \\___|_|   \\__|" << endl;
    //Ask Question
    char loop;
    do {
        string sentence;
        string search;
        size_t pos;
        int count;

        cout << "Ask Gilbert a question:" << endl;
        getline(cin, sentence);

        //Words    
        count = 0;
        search = "apple";
        pos = sentence.find(search);
        if (pos != string::npos && count == 0) {
            cout << "i likez thouse.";
            ++count;
        }

        count = 0;
        search = "pear";
        pos = sentence.find(search);
        if (pos != string::npos && count == 0) {
            cout << "i likez thou.";
            ++count;
        }

        //End Loop
        cout << endl << "Ask another?(Y/N)" << endl;
        cin >> loop;
        cout << string(3, '\n');
    } while (loop == 'y' || loop == 'Y');
    if (loop == 'n') {
        cout << "i didnt like you anyways...";
        return 0;

    }
}

Answer 1

问题出在以下声明中:

cin >> loop;

例如'y',当用户输入一个字母时,按回车键.它实际上会在输入缓冲区中存储两个字符,'y'并且'\n'.角色'y'存储在loop,但'\n'遗体.因此,当内部do-while循环到达此行时:

getline (cin, sentence);

由于\n缓冲区中已有一个字符,因此getline会接受它,并且不会要求用户输入更多字符.因此,你看到了奇怪的提示输出.

请尝试以下方法:

cin >> loop;
cin.ignore();

通过上述更改,它应该按预期工作.