Thread: Help with first c++ program (math-related)

Well, this is my first c++ program assignment.
I was pretty proud of myself after I finished it but I'm having a small problem.

This program is designed to output a few weighted grades from a set of 4 scores.

The quizzes need to be weighted at 30% and the tests weighted at 70%

It's set up, and I think it runs just fine, but my problem is, my weighted scores are not the same as the example's is

The sample output is

How many student you want to process: 1
Enter next student’s name: Doug Talbert
Enter quiz 1 quiz 2 test 1 and test 2 scores of Doug Talbert: 93 96 99 97
Name: Doug Talbert
Quiz: 27
Test: 67
Total: 94
Grade: A

Here is my output

How many student you want to process: 1
Enter next student’s name: Doug Talbert
Enter quiz 1 quiz 2 test 1 and test 2 scores of Doug Talbert: 93 96 99 97
Name: Doug Talbert
Quiz: 28.35
Test: 68.6
Total: 96
Grade: A

http://img571.imageshack.us/img571/379/problemeu.jpg


As you can see, I'm not getting exactly what I should.

Also, I have one more problem, how do I get rid of those pesky decimals :P

Code:

/*****************************\
*                             *
*   9/30/2010                 *
*   Programming Assignment 1  *
\*****************************/

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

using namespace std;

int main(){

	int totalquiz,totaltest,total,students,quiz1,quiz2,test1,test2;
	char grade;
	char name[21];

	cout << "How many student you want to process: ";	
	cin >> students;
	cout << endl;

	if (students >=1){

		if (students<=50){	
			
			while (students){															 
				cin.ignore();
				cout << "Enter next student's name: ";
				cin.getline (name,21);
				cout << endl;

				cout << "Enter quiz 1 quiz 2 test 1 and test 2 scores of " << name << " ";
				cin >> quiz1 >> quiz2 >> test1 >> test2;

				totalquiz = (quiz1+quiz2) / 2 * .3 ;
				totaltest = (test1+test2) / 2 * .7 ;
				total = totalquiz + totaltest;

				if (total >= 90)
					grade = 'A';
				else if (total >= 80)
					grade = 'B';
				else if (total >= 70)
					grade = 'C';
				else if (total >= 60)
					grade = 'D';
				else if (total <  60)
					grade = 'F';

				cout << endl;
				cout << setw(15) << "Name:" << setw(21) << name << endl;
				cout << setw(15) << "Quiz:" << setw(21) << totalquiz << endl;
				cout << setw(15) << "Test:" << setw(21) << totaltest << endl;
				cout << setw(16) << "Total:" << setw(20) << total << endl;
				cout << setw(16) << "Grade:" << setw(19) << grade << endl << endl;
				students--;
			}
		}
		else{
			cout << "Number of students must be 50 or less, please try again\n";
			return 0;}
		}
	else{ 
		cout << "Number of students must be a number over 0, please try again\n";
		return 0;}
	}

> PS> my code style is not complete, I was going to beautify it after I finish with comments ect.. :P
More people might read it if it looks good to start with.

Try doing the whole thing as integer maths, so you truncate at every possible step.

quiz1/2 + quiz2/2 != (quiz1+quiz2)/2
when doing integer maths.

> i guess I was wrong.
It was wrong to assume that you could post any randomly formatted crud and expect people to read it.

Even if it is only a snippet.

But then you've edited the original, and I no longer care to debate the issue with you.

lol, the original was like that except for about 5 blank lines, I guess I should really think carefully before posting on this forum.

anyways thanks, you have been very helpful, as I said this is my 1st program
I should be entitled to a few mistakes

I'll try to figure this out, I'll post again on this forum when I have finished this class on c++, maybe then I'll be able to organize my information to everyone's standards

Originally Posted by Salem

quiz1/2 + quiz2/2 != (quiz1+quiz2)/2
when doing integer maths.

> i guess I was wrong.
It was wrong to assume that you could post any randomly formatted crud and expect people to read it.

Even if it is only a snippet.

But then you've edited the original, and I no longer care to debate the issue with you.