C ++ CIN cin随机跳过 [英] C++ CIN cin skips randomly
问题描述
我有这个程序,但cin在随机跳过我的意思是有时它,有时它不。任何想法如何解决这个问题?
I have this program, but cin in randomly skips.. I mean sometimes it does, and sometimes it doesn't. Any ideas how to fix this?
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++;
}
}
OK我想出来了。对于任何想知道这里更新的代码的人:
OK I figured it out. For anyone that would like to know here's the updated code:
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++;
}
推荐答案
您的输入中有空格,>>运算符将其视为特定输入项的结尾。 iostreams >>运算符实际上不是为交互式输入而设计的,特别是对于字符串,你应该考虑使用getline()。
I would guess that some of your inputs have spaces in them, which the >> operator treats as the end of a particular input item. The iostreams >> operator is really not designed for interactive input, particularly for strings - you should consider using getline() instead.
assignment = new Assignment(assignment_name);
最好写成:
Assignment assignment(assignment_name);
你应该尽可能避免在代码中使用'new',照顾对象的生命期。
you should avoid the use of 'new' in your code wherever possible, and instead let the compiler take care of object lifetimes for you.
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