while loop running before getline gets input

Question

I'm doing this assignment for class, when I run the code, the last else statement in the last while loop runs before the getline gets input, basically my output looks like this: Enter the name of the file (include extension): grades.txt Options: (enter your selection) Exit, Display average, Display grades, Add new grade Error: Invalid input Options: (enter your selection) Exit, Display average, Display grades, Add new grade

It takes input after all of this but as you can see the statement meant to handle invalid input runs before the getline gets input

#include <iostream>
#include <fstream>
#include <string>
#include <vector>

using namespace std;

int main()
{
    ifstream gradeList;
    string fileName;
    int tempItem;
    vector<int> gradesVector;`your text`
    string response;
    cout << "Enter the name of the file (include extension): ";
    cin >> fileName;
    gradeList.open(fileName);

    while (!gradeList.is_open()) {
        cout << endl << "Error: file doesn't exist." << endl;

        cout << "Enter a file name (include extension): ";
        cin >> fileName;
        gradeList.open(fileName);
    }

    while (!gradeList.eof()) {
        gradeList >> tempItem;
        gradesVector.push_back(tempItem);
    }
    
    gradeList.close();

    cout << "Options: (enter your selection)" << endl;
    cout << "Exit, Display average, Display grades, Add new grade" << endl;
    getline(cin, response);
    

    while (response != "Exit") {
        if (response == "Display average") {
            int totalGrades;
            int averageGrade;
            int i;
            totalGrades = 0;
            for (i = 0; i < gradesVector.size(); ++i) {
                totalGrades = totalGrades + gradesVector[i];
            }

            averageGrade = totalGrades / (gradesVector.size() + 1);
            cout << "The average grade is: " << averageGrade << endl;

            cout << "Options: (enter your selection)" << endl;
            cout << "Exit, Display average, Display grades, Add new grade" << endl;
            getline(cin, response);
        }
        else if (response == "Display grades") {
            int i;
            
            for (i = 0; i < gradesVector.size(); ++i) {
                cout << "Grade " << i+1 << ": " << gradesVector[i] << endl;
            }
            cout << "Options: (enter your selection)" << endl;
            cout << "Exit, Display average, Display grades, Add new grade" << endl;
            getline(cin, response);
        }
        else if (response == "Add new grade") {
            int newGrade;
            newGrade = -1;
            while (newGrade < 0 || newGrade > 100) {
                cout << "Enter new grade: ";
                cin >> newGrade;
                cin.clear();
                cout << endl;
            }
            gradesVector.push_back(newGrade);
            cout << "Options: (enter your selection)" << endl;
            cout << "Exit, Display average, Display grades, Add new grade" << endl;

            getline(cin, response);
        }
        else{
            cout << "Error: Invalid input" << endl;
            cout << "Options: (enter your selection)" << endl;
            cout << "Exit, Display average, Display grades, Add new grade" << endl;
            cin.clear();
            getline(cin, response);
        }
    }



}

I really dont know what to try because I can't find anybody with the same issue

And when you used your debugger to run this code, what did you see? This is what a debugger is for and if you don't know how to use it, this is a good opportunity to learn running your program one line at a time in a debugger, monitoring all variables and their values as they change and analysing your program's logic and execution. It should be possible for you to use your debugger to find all simple problems in this and all future programs you write, all by yourself. Do you know how to use a debugger? Knowing how to effectively use a debugger is a required skill for every C++ developer. — Sam Varshavchik, Feb 10 '23 at 18:44
This doesn't address the question, but get in the habit of initializing objects with meaningful values rather than default-initializing them and then overwriting the default values. In this case that means changing `std::ifstream gradeList; ... std::cin >> fileName; gradeList.open(filename);` to `std::cin >> fileName; std::ifstream gradeList(fileName);`. Also, you don't need to call `gradeList.close();`; the destructor will do that. — Pete Becker, Feb 10 '23 at 19:53
Nothing in this code needs the extra stuff that `std::endl` does. `'\n'` ends a line. — Pete Becker, Feb 10 '23 at 19:54
Im gonna be completey honest, I'm still new to programming and have never used a debugger, how would I go about using that with visual studio? Also thanks for the advice, I really just use endl out of habit and I'll try to make a habit of initializing the variables like you said — Crusty Cain, Feb 10 '23 at 20:04

while loop running before getline gets input

0 Answers0