C++ CIN cin随机跳过

Question

我有这个程序，但是cin在随机跳过..我的意思是有时会，有时不会。你有什么办法解决这个问题吗？

    int main(){ 


        /** get course name, number of students, and assignment name **/
        string course_name;
        int numb_students;
        string assignment_name;
        Assignment* assignment;

        cout << "Enter the name of the course" << endl;
        cin >> course_name;

        cout << "Enter the number of students" << endl;
        cin >> numb_students;   

        cout << "Enter the name of the assignment" << endl;
        cin >> assignment_name;

        assignment = new Assignment(assignment_name);

        /** iterate asking for student name and score **/
        int i = 0;
        string student_name;
        double student_score = 0.0;
        while( i < numb_students ){

            cout << "Enter the name for student #" << i << endl;
            cin >> student_name;
            cout << "Enter the score for student #" << i << endl;
            cin >> student_score;
            assignment->addScore( Student( student_name, student_score ));
            i++;
        }
}

好了，我想通了。对于任何想知道的人来说，这里有更新的代码：

int main(){ 

    /** get course name, number of students, and assignment name **/
    string course_name;
    int numb_students;
    string assignment_name;

    cout << "Enter the name of the course" << endl;
    getline(cin, course_name);

    cout << "Enter the number of students" << endl;
    string temp;
    getline(cin, temp);
    numb_students = atoi(temp.c_str());

    cout << "Enter the name of the assignment" << endl;
    getline(cin, assignment_name);

    Assignment assignment(assignment_name);

    /** iterate asking for student name and score **/
    int i = 0;
    string student_name;
    double student_score = 0.0;
    while( i < numb_students ){

        cout << "Enter the name for student #" << i+1 << endl;
        getline(cin, student_name);     
        cout << "Enter the score for student #" << i+1 << endl;
        getline(cin, temp);
        student_score = atof(temp.c_str());
        assignment.addScore( Student( student_name, student_score ));
        i++;
    }

Answer 1

我猜您的一些输入中有空格，>>操作符将其视为特定输入项的末尾。iostreams >>操作符实际上不是为交互式输入而设计的，特别是对于字符串-您应该考虑使用getline()来代替。

此外，您还不需要使用动态分配：

assignment = new Assignment(assignment_name);

最好写成：

Assignment assignment(assignment_name);

你应该尽可能避免在你的代码中使用'new‘，而是让编译器为你关注对象的生命周期。