C++ CIN cin 随机跳过

Question

我有这个程序，但 cin 会随机跳过。我的意思是有时会跳过，有时不会。有什么想法如何解决这个问题吗？

    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++;
        }
}

好吧，我想通了。对于任何想知道这里是更新后的代码的人：

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

我猜你的一些输入中有空格，其中 >>运算符视为特定输入项的结尾。 iostreams>>运算符实际上并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() 代替。

另外，您不必要地使用动态分配：

assignment = new Assignment(assignment_name);

最好写为：

Assignment assignment(assignment_name);

您应该尽可能避免在代码中使用“new”，而是让编译器为您处理对象生命周期。