Thread: Dynamic Array Problem

Hello,

I am attempting to create a small gradebook application for a project. I am using dynamic 1-d arrays as well as one dynamic 2-d array. I'll try not to post too much code, but rather post the scope of the problem. The code (left out many parts of it):

Code:

void main()
{
	apstring *grade_types, *last_names, name;
	double *averages, *grade_weights;
	int **grades, *ids, num_grades, period, size;

	name = get_apstring("class name");
	period = get_integer("class period");
	size = get_integer("class size");
	
	averages = new double[size];
	ids = new int[size];
	last_names = new apstring[size];

	for (int i = 0; i < size; ++i)
	{
		cout << "Enter student # " << i + 1 << "'s last name." << endl;
		cin >> last_names[i];

		cout << "Enter " << last_names[i] << "'s ID number." << endl;
		cin >> ids[i];
	}

	num_grades = get_integer("number of grade categories");

	grades = new int*[size];

	for (i = 0; i < size; ++i) {
		grades[i] = new int[num_grades];

		for (int j = 0; j < size; ++j)
		{
			grades[i][j] = 0;
		}
	}

	grade_types = new apstring[num_grades];
	grade_weights = new double[num_grades];

	for (i = 0; i < num_grades; ++i)
	{
		cout << "Enter grade type #" << i + 1 << "." << endl;
		cin >> grade_types[i];

		cout << "Enter weight for " << grade_types[i] << "." << endl;
		cin >> grade_weights[i];
	}

	for (i = 0; i < size; ++i)
	{
		for (int j = 0; j < num_grades; ++j)
		{
			cout << "Enter a grade." << endl;
			cin >> grades[i][j];

			averages[i] += grades[i][j] * grade_weights[j];
		}
	}

	for (i = 0; i < size; ++i)
	{
		cout << last_names[i] << setw(15 - last_names[i].length());
		cout << ids[i] << " ";

		for (int j = 0; j < num_grades; ++j)
		{
			cout << grades[i][j] << " ";
		}

		cout << averages[i] << " ";

[Continues...]

I have no syntax errors, but one logic error that I cannot seem to fix. For some reason the following code does not work the way it's supposed to:

Code:

averages[i] += grades[i][j] * grade_weights[j];

Which causes this code:

Code:

cout << averages[i] << " ";

...to print a strange float number (like 1.6245... or something like that). I'm thinking that averages[i] may be undeclared. But how could it be if I already declared it before?

Any assistance is appreciated.

nm fixed it myself...

Just curious?
Was the problem in casting your variables?