Quiz Averages

[blade1771]

I am having trouble in including the class average and the individual averages. This is what I have so far. Any help would be appreciated.

[#include <iostream>
#include <fstream>
#include <string>
#include <iomanip>

using namespace std;

int main()
{
const int SIZE = 1000;
string studentID[SIZE];
string flag = "0";
double quiz1[SIZE];
double quiz2[SIZE];
double quiz3[SIZE];
double quiz4[SIZE];
double average[SIZE] = (quiz1+quiz2+quiz3+quiz4)/4;
int i = 0;

while (i < SIZE)
{
cout << "Student Id (-1 to exit): ";
cin >> flag;

if (flag == "-1")
break;

studentID[i] = flag;

cout << "Input quiz1: ";
cin >> quiz1[i];

cout << "Input quiz2: ";
cin >> quiz2[i];

cout << "Input quiz3: ";
cin >> quiz3[i];

cout << "Input quiz4: ";
cin >> quiz4[i];

cout << average << endl;

i++;
}


ofstream output;

output.open("Grades.txt");

for (int j = 0; j < i; j++)
{
cout << "Student ID: " << fixed << setprecision(2) << studentID[j] << endl;
cout << "Quiz 1: " << fixed << setprecision(2) << quiz1[j] << endl;
cout << "Quiz 2: " << fixed << setprecision(2) << quiz2[j] << endl;
cout << "Quiz 3: " << fixed << setprecision(2) << quiz3[j] << endl;
cout << "Quiz 4: " << fixed << setprecision(2) << quiz4[j] << endl;
cout << endl;
}

for (int j = 0; j < i; j++)
{
output << studentID[j] << endl;
output << quiz1[j] << endl;
output << quiz2[j] << endl;
output << quiz3[j] << endl;
output << quiz4[j] << endl;
}

output.close();

ifstream input;

input.open("Grades.txt");

for (int j = 0; j < i; j++)
{
input >> studentID[j];
input >> quiz1[j];
input >> quiz2[j];
input >> quiz3[j];
input >> quiz4[j];
}

input.close();

for (int j = 0; j < i; j++)
{
cout << "Student ID: " << fixed << setprecision(2) << studentID[j] << endl;
cout << "Quiz 1: " << fixed << setprecision(2) << quiz1[j] << endl;
cout << "Quiz 2: " << fixed << setprecision(2) << quiz2[j] << endl;
cout << "Quiz 3: " << fixed << setprecision(2) << quiz3[j] << endl;
cout << "Quiz 4: " << fixed << setprecision(2) << quiz4[j] << endl;
cout << endl;
}

system("Pause");

return 0;
}
]

[pheininger]

I am assuming you are in a class. Have you studied struct (structures) yet?

double average[SIZE] = (quiz1+quiz2+quiz3+quiz4)/4;
This does not do what you think it does.

You need to calculate the individual student averages before this statement:cout << average << endl;

Please use code tags when posting your code so that the indentation is preserved.

[AndyMc]

Remove:

double average[SIZE] = (quiz1+quiz2+quiz3+quiz4)/4;

and before outputting the average calculate it in the loop instead:

double average = (quiz1[i]+quiz2[i]+quiz3[i]+quiz4[i]) / 4;
cout << average << endl;

Note that the use of the system command:

system("Pause");

is generally frowned upon. There are plenty of threads as to why that is on the forum already, you might want to replace it with a call to:

cin.get();

You do realise though, that for this program to work, someone is going to have to type in 4000 numbers! Wouldn't reading from a file be better?