CODEWITHSUNDEEP
c++
Quester
Quester

Reputation: 2009

getline(cin, var) issue. Program ignores the command

I have an issue with the code in line 23. (Please see code below)

When I use "cin >> studentNum"; I have no issue and the program reads the one string for the firstname, but if I want to gather more data using "getline(cin, studentNum)" to read more strings like the full name, the program just skips the command and asks for the score .

Why is that? 

#include <iostream>
#include <string>

using namespace std;

int main()
{
    int studentNum, testNum, i, j;
    double sum, testScore, average;
    string studentName;
    i = 0;

    // asking user for input

    cout << "Please enter the number of students in this classroom: " << endl;
    cin >> studentNum;

    cout << "Now enter the number of tests each student has taken in this class: " << endl;
    cin >> testNum;
    while (i < studentNum)
    {
        cout << endl << "Now please enter the firstname of the student: " << endl;
        cin >> studentName; //**My Problem is in this line ###########**
        j = 0;
        sum = 0;
        while (j < testNum)
        {
            cout << "Please enter the score of each test, then hit enter: " << endl;
            cin >> testScore;
            sum += testScore;
            j++;
        }
    i++;
    }
}

Upvotes: 0

Views: 73

Answers (2)

wuqiang
wuqiang

Reputation: 644

You should clear the state flag and flush the steram

cin.clear();  
std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
getline(cin, studentName);

Upvotes: 1

user3920237
user3920237

Reputation:

It sounds to me that you need to use cin.ignore. You need to discard the linefeed character still present in the stream.

#include <limits>
// This is not a C++11 feature, works fine in C++98/03
std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
std::getline(std::cin, studentName);

By default, operator>> will skip leading whitespace, i.e. classifed by std::ctype. You can see that in a test program by turning this behavior off with unsetf(std::ios_base::skipws), that it will extract the whitespace. By using cin.ignore, you can simply discard it since it's undesirable. For more information, see cin and getline skipping input.

Upvotes: 2

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