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Why wont My Program display the Average?

coutman1026 (2)
Why wont My Program display the Average? I keep getting numbers like -1.231230e044 no matter what i do...

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#include <iostream>
#include <string>
#include <iomanip>


const int N = 10;		//# of students

using namespace std;

struct Students
{
	string Name;		//student name
	double IDnum;		//student id number
	double Average;		//student average
	double *Tests = nullptr;		//student test scores
	string Grade;		//student Letter grade
};

void Print(Students *);	//Function to display

int main()
{
	//dynamically allocating an array of structures
	Students *Class1;
	Class1 = new Students[N];

	//find how many test scores per student
	int num_of_tests;
	cout << "How many test scores per student?" << endl;
	cin >> num_of_tests;
	//to check if its negative or not
	while (num_of_tests < 0)
	{
		cout << "How many test scores per student?" << endl;
		cin >> num_of_tests;
	}

	//for loop to get student name
	for (int counter = 0; counter < N; counter++)
	{
		cout << "What is the name of Student " << counter << "?" << endl;
		cin >> Class1[counter].Name;
	}

	// For loop to get student ID
	for (int counter = 0; counter < N; counter++)
	{
		cout << "What is the Student ID of " << Class1[counter].Name << endl;
		cin >> Class1[counter].IDnum;
	}

	//for loop to declare new int
	for (int counter = 0; counter < N; counter++)
	{
		Class1[counter].Tests = new double[num_of_tests];
	}



	//for loops for getting test scores
	for (int i = 0; i < num_of_tests; i++)
	{
		for (int counter = 0; counter < N; counter++)
		{
			cout << "What is the test score of " << Class1[counter].Name << "?" << endl;
			cin >> Class1[counter].Tests[i];
			//to check if its negative or not
			while (Class1[counter].Tests[i] < 0)
			{
				cout << "What is the test score " << Class1[counter].Name << "?" << endl;
				cin >> Class1[counter].Tests[i];
				
			}
			
			//finding the average
			Class1[counter].Average += Class1[counter].Average;
			Class1[counter].Average /= num_of_tests;
		}
	}

	cout << endl << endl;


	//function call
	Print(Class1);

	delete[] Class1;
	system("pause");
	return 0;
}


void Print(Students Class1[])
{
	cout << endl << endl;
	//create table
	cout << "Name \t\t\t Grade" << endl;
	cout << "----------------------------------------------------------" << endl;


	//display grade
	for (int counter = 0; counter < N; counter++)
	{
		if (Class1[counter].Average <= 100 && Class1[counter].Average >= 91)
		{
			Class1[counter].Grade = 'A';
			cout << Class1[counter].Name << " \t\t\t " << Class1[counter].Grade << endl;
		}
		if (Class1[counter].Average <= 90 && Class1[counter].Average >= 81)
		{
			Class1[counter].Grade = 'B';
			cout << Class1[counter].Name << " \t\t\t " << Class1[counter].Grade << endl;
		}
		if (Class1[counter].Average <= 80 && Class1[counter].Average >= 71)
		{
			Class1[counter].Grade = 'C';
			cout << Class1[counter].Name << " \t\t\t " << Class1[counter].Grade << endl;
		}
		if (Class1[counter].Average <= 70 && Class1[counter].Average >= 61)
		{
			Class1[counter].Grade = 'D';
			cout << Class1[counter].Name << " \t\t\t " << Class1[counter].Grade << endl;
		}
		if (Class1[counter].Average <= 60 && Class1[counter].Average >= 0)
		{
			Class1[counter].Grade = 'F';
			cout << Class1[counter].Name << " \t\t\t " << Class1[counter].Grade << endl;
		}

	}

	cout << endl << endl;
	//create table
	cout << "Name \t\t\t ID" << endl;
	cout << "----------------------------------------------------------" << endl;
	

	//for loop to display student ID
	for (int counter = 0; counter < N; counter++)
	{
		cout << Class1[counter].Name << " \t\t\t " << Class1[counter].IDnum << endl;
	}

cout << endl << endl;
	
	//create table
	cout << "Name \t\t\t Average Test Scores" << endl;
	cout << "----------------------------------------------------------" << endl;

	//for loop to display test score averages
	for (int counter = 0; counter < N; counter++)
	{
		cout << Class1[counter].Name << " \t\t\t " << Class1[counter].Average << endl;
	}
}
closed account (N8RzwA7f)
try initializing average to zero at the start of your program.
I didn't fully read the code but it looks like some garbage value in memory is used in the display grade loop and it immediately leaves the loop as if doesn't match any if statement value.
SamuelAdams (1535)
I agree, always initialize all your variables.
SakurasouBusters (732)
Your program works fine.
How many test scores per student?
2
What is the name of Student 0?
g
What is the name of Student 1?
g
What is the name of Student 2?
g
What is the name of Student 3?
gdsf
What is the name of Student 4?
sdf
What is the name of Student 5?
sd
What is the name of Student 6?
fsd
What is the name of Student 7?
fsd
What is the name of Student 8?
f
What is the name of Student 9?
f
What is the Student ID of g
435
What is the Student ID of g
43
What is the Student ID of g
543
What is the Student ID of gdsf

534534
What is the Student ID of sdf
5
What is the Student ID of sd
34
What is the Student ID of fsd
534
What is the Student ID of fsd
5
What is the Student ID of f
34
What is the Student ID of f
5
What is the test score of g?
435345
What is the test score of g?
34
What is the test score of g?
534
What is the test score of gdsf?
5
What is the test score of sdf?
34
What is the test score of sd?
534
What is the test score of fsd?
5
What is the test score of fsd?
34456
What is the test score of f?
5476
What is the test score of f?
544
What is the test score of g?
654
What is the test score of g?
6
What is the test score of g?
45
What is the test score of gdsf?
654
What is the test score of sdf?
6
What is the test score of sd?
456
What is the test score of fsd?
54645
What is the test score of fsd?
645
What is the test score of f?
6
What is the test score of f?
4545




Name                     Grade
----------------------------------------------------------
g                        F
sdf                      F


Name                     ID
----------------------------------------------------------
g                        435
g                        43
g                        543
gdsf                     534534
sdf                      5
sd                       34
fsd                      534
fsd                      5
f                        34
f                        5


Name                     Average Test Scores
----------------------------------------------------------
g                        435999
g                        40
g                        579
gdsf                     659
sdf                      40
sd                       990
fsd                      54650
fsd                      35101
f                        5482
f                        5089


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#include <iostream>
#include <string>
#include <iomanip>


const int N = 10;		//# of students

using namespace std;

struct Students
{
	Students() : Tests(NULL), Average(0) {}

	string Name;		//student name
	double IDnum;		//student id number
	double Average;		//student average
	double *Tests;		//student test scores
	string Grade;		//student Letter grade
};

void Print(Students *);	//Function to display

int main()
{
	//dynamically allocating an array of structures
	Students *Class1;
	Class1 = new Students[N];
	int counter;

	//find how many test scores per student
	int num_of_tests;
	cout << "How many test scores per student?" << endl;
	cin >> num_of_tests;
	//to check if its negative or not
	while (num_of_tests < 0)
	{
		cout << "How many test scores per student?" << endl;
		cin >> num_of_tests;
	}

	//for loop to get student name
	for (counter = 0; counter < N; counter++)
	{
		cout << "What is the name of Student " << counter << "?" << endl;
		cin >> Class1[counter].Name;
	}

	// For loop to get student ID
	for (counter = 0; counter < N; counter++)
	{
		cout << "What is the Student ID of " << Class1[counter].Name << endl;
		cin >> Class1[counter].IDnum;
	}

	//for loop to declare new int
	for (counter = 0; counter < N; counter++)
	{
		Class1[counter].Tests = new double[num_of_tests];
	}


	//for loops for getting test scores
	for (int i = 0; i < num_of_tests; i++)
	{
		for (counter = 0; counter < N; counter++)
		{
			cout << "What is the test score of " << Class1[counter].Name << "?" << endl;
			cin >> Class1[counter].Tests[i];
			//to check if its negative or not
			while (Class1[counter].Tests[i] < 0)
			{
				cout << "What is the test score " << Class1[counter].Name << "?" << endl;
				cin >> Class1[counter].Tests[i];
			}
			
			//finding the average
			Class1[counter].Average += Class1[counter].Tests[i];
		}
			Class1[counter].Average /= num_of_tests;
	}

	cout << endl << endl;


	//function call
	Print(Class1);

	delete[] Class1;
	system("pause");
	return 0;
}


void Print(Students Class1[])
{
	cout << endl << endl;
	//create table
	cout << "Name \t\t\t Grade" << endl;
	cout << "----------------------------------------------------------" << endl;


	//display grade
	for (int counter = 0; counter < N; counter++)
	{
		if (Class1[counter].Average <= 100 && Class1[counter].Average >= 91)
		{
			Class1[counter].Grade = 'A';
			cout << Class1[counter].Name << " \t\t\t " << Class1[counter].Grade << endl;
		}
		if (Class1[counter].Average <= 90 && Class1[counter].Average >= 81)
		{
			Class1[counter].Grade = 'B';
			cout << Class1[counter].Name << " \t\t\t " << Class1[counter].Grade << endl;
		}
		if (Class1[counter].Average <= 80 && Class1[counter].Average >= 71)
		{
			Class1[counter].Grade = 'C';
			cout << Class1[counter].Name << " \t\t\t " << Class1[counter].Grade << endl;
		}
		if (Class1[counter].Average <= 70 && Class1[counter].Average >= 61)
		{
			Class1[counter].Grade = 'D';
			cout << Class1[counter].Name << " \t\t\t " << Class1[counter].Grade << endl;
		}
		if (Class1[counter].Average <= 60 && Class1[counter].Average >= 0)
		{
			Class1[counter].Grade = 'F';
			cout << Class1[counter].Name << " \t\t\t " << Class1[counter].Grade << endl;
		}

	}

	cout << endl << endl;
	//create table
	cout << "Name \t\t\t ID" << endl;
	cout << "----------------------------------------------------------" << endl;
	

	//for loop to display student ID
	for (counter = 0; counter < N; counter++)
	{
		cout << Class1[counter].Name << " \t\t\t " << Class1[counter].IDnum << endl;
	}

cout << endl << endl;
	
	//create table
	cout << "Name \t\t\t Average Test Scores" << endl;
	cout << "----------------------------------------------------------" << endl;

	//for loop to display test score averages
	for (counter = 0; counter < N; counter++)
	{
		cout << Class1[counter].Name << " \t\t\t " << Class1[counter].Average << endl;
	}
}
coutman1026 (2)
Thanks so much! I put it back into Visual C++ and it worked perfectly!

Last question:

What did you do here?

 
 
Students() : Tests(NULL), Average(0) {}
Last edited on
SakurasouBusters (732)
Member initializer list.
http://en.cppreference.com/w/cpp/language/initializer_list
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