Using cin and while to loop until done

[amcandrew]

Hello: the following code is meant to capture grade data input in a console application. After that data for one student has been captured, the application askes whether data for another student should be captured. The program uses a while loop, where the boolean "newStudent" should determine whether to re-loop or proceed to the last steps of the program. I do not think that the input section at the end of the while loop is working?


int main() {

bool newStudent=true;
int resp;


while(newStudent) {
get grade data and put into vectors--this all seems to work

cout << "Will there be another student's grades? " << endl;
cout<<"If yes, type 1. If no, type 0."<<endl;
cin >> resp;
if (resp == 1) newStudent = true; else newStudent=false;
}

DISPLAY THE RESULTS

getch();
return 0;

} // end of main

[amcandrew]

After working more on this, I think that the piece of code originally shown is probably ok. What seems to be happening is that when the program runs through the while loop to obtain student grade data the second time (i.e. newStudent is true), the "cin>>" lines are not waiting for me to provide input the way that they did the first time through the loop. (I do see the cout lines that are prompting for the data input.
Can anyone see why the cin would not work on the second pass through the while loop?

The whole loop is pasted here
while (newStudent) {

cout<<"Hey, what's your first name?"<<endl<<endl;
cin >> name;
nameVec.push_back(name);
cout << "Hello "<<name<<"!"<<endl<<endl;
cout<<"Please input your various scores as prompted below:"<<endl;
cout<<"Please enter your final exam grade."<<endl;
cin>>final;
cout<<"Please enter your midterm exam grade."<<endl;
cin>>midterm;
cout<<"Please enter your homework grades separated by "
<< "spaces. When you are done, go to a new line and input "
<<"the end of file character" <<endl;

while (cin>>hmwk) {
hmwkVec.push_back(hmwk);
}
// determine the length of the homework vector
/*
vecsz hmwkSize=hmwkVec.size();

// calculate the average homework score
int total = 0;
for (int i=0; i!=hmwkSize; i++)
total += hmwkVec[i];

if (hmwkSize == 0) return 5; //breaking out here.
avgHmwk = total/hmwkSize;
*/
avgHmwk = 75;
// calculate the overall grade

grade = 0.4*final + 0.2*midterm + 0.4*avgHmwk;
gradeVec.push_back(grade);
hmwkVec.clear();
// ask whether we will be collecting data for another student

cout << "Will there be another student's grades? (y/n) " << endl;
resp=getch();
cout<<resp<<endl;
getch();
if (resp == 'n') newStudent = false; else newStudent=true;
cout<<"newStudent value is "<< newStudent<<endl;

} //end of while

// print out the names and the grades
sizeNameVec = nameVec.size();
cout<<"Here are the students and their grades"<<endl<<endl;
for (int i=0; i!=sizeNameVec; i++)
cout<<nameVec[i]<<"\t"<<gradeVec[i]<<end;




getch();
return 0;
} //end of main

[CornedBee]

It probably wouldn't work if you enter anything else than a number - that sets the stream to a "bad" state in which it won't continue until you reset it.

[amcandrew]

That's right. The problem lies with the CIN being put into an error state. Including a clear statement after the reading of data solved the problem.

Thank you.