Difficulty with getline()

[thisguyehisaguy]

Hey all,
I can't seem to get the getline() function to work properly for me. I'm trying to use it so that I can store full names in a string array consisting of user-specified size n elements. I've tried a lot of different tweaks (different headers, using a string var instead, etc) all to no avail. Help, please. This was an exercise for my class but I don't think accepting whitespace is a requirement and I've already submitted it using cin instead. I just want to understand why I can't make it work. I doubt that any of the other code is impacting it but I include the entire program just in case. Also, when I tried building this in Visual Studio it wouldn't compile at all! (I did #include "stdafx.h" so that's not why... I just got a bunch of errors. If anyone is interested in what they are, I'll share but it's really besides the point since I'm only concerned with programming for linux/unix consoles for the time being.)

#include <iostream>
using namespace std;
double score(double a, double b, double c) {
    double max, min, final_score;
    if(a > b) {
        max = a;
        min = b;
    }
    else {
        max = b;
        min = a;
    }
    final_score = max * .35 + min * .3 + c * .35;
    return final_score;
}
void letter(double a) {
    if(a > 90)
        cout << "A";
    else if(a > 80)
        cout << "B";
    else if(a > 70)
        cout << "C";
    else if(a > 60)
        cout << "D";
    else
        cout << "F";
    return;
}
int main() {
    int n, x, y;
    cout << "How many students? ";
    cin >> n;
    double grade[n][3];
    string student[n];
    for(x = 0; x < n; x++) {
        cout << "Name: ";
        getline(cin, student[x]);
        for(y = 0; y < 3; y++) {
            cout << "Exam "<< y + 1 << " grade: ";
            cin >> grade[x][y];
        }
    }
    for(x = 0; x < n; x++) {
        cout << student[x] << ": ";
        letter(score(grade[x][0], grade[x][1], grade[x][2]));
        cout << endl;
    }
    return 0;
}

[Chervil]

#include <string>

[thisguyehisaguy]

@Chervil, thanks for the suggestion but I tried that as well as

#include <cstring> 

to no avail... It compiles fine but the program behaves as if getline() was not even there... or as if only the return key was hit.

[Chervil]

After the user enters the input for this line, cin >> n; there will be a newline character remaining in the input buffer.

If the program then does a getline() it will retrieve everything up to the newline character (which is then discarded). The result is an empty string.

The answer is to use cin.ignore() after cin >> n; before the getline() in order to remove the unwanted newline character.

[thisguyehisaguy]

Thanks, Chervil. Worked like a charm :)

I put it in the for loop so that it would discard the newline from each call to cin

 for(x = 0; x < n; x++) {
        cin.ignore();
        cout << "Name: ";
        getline(cin, student[x]);
        for(y = 0; y < 3; y++) {
            cout << "Exam "<< y + 1 << " grade: ";
            cin >> grade[x][y];
        }

All the best,
David