The assignment was to graph a line within 10 units of the origin
after the user inputs the slope and y-intercept.
Sounded much easier than it was, I gave it a shot but I can't
get it to print correctly. To be honest I just dont know if im
headed in remotely the right direction, any help would be greatly appreciated.
I think the problem is passing my counter i to the function printline() can that be done?

#include<iostream>
#include<iomanip>
using namespace std;
// 
//
//
// Graph a line when given the linear equation.
//
void graph(double, double);
void printline(double, double, int);
//
int main()   {
	
	cout << "Please enter the slope and y-intercept" << endl;
	cout << "of the line you would like to graph." << endl;
	
	//take input
	double slope, intercept;
	cout << "Slope: ";
	cin >> slope;
	cout << "Y-Intercept: ";
	cin >> intercept;
	cout << endl;

	//graph the line
	graph(slope, intercept);
	
	cout << endl;
	

	cout << "The full equation of your line is" << endl;
	cout << "y = " << slope << "x + " << intercept;
	
	cin.get();
	cin.get();
	return 0;
}

void graph(double slope, double intercept)  
{
// tried to use printline() for lines not on grid
// and print big line where it should be on a 
// cartesian plane, at 0
	int i;
	for(i=10; i>(-10); i--)
		if (i=0)
			cout << "---------------------" << endl;
		else
			printline(slope, intercept, i);
}

void printline(double slope, double intercept, int i)  {
	
	double xcoord;

  //xcoord is the distance from (-10) the asterisk should print
	xcoord=(i-intercept)/slope;
	if (xcoord<0)
	// if its negative i flip it to positive and subtract it 
                // from ten to make it the proper distance 
                // from the y-axis
               {	xcoord=xcoord*(-1);
		cout << setw(10-xcoord) << "*";
		cout << setw(xcoord+1) << "|";
		cout << "          " << endl;
	}
	
                else
                // otherwise i print the blankspace, the y axis,
                // and then the proper distance fromthe y-axis
                // once i have my asterisk in the right spot i fill in the rest with blanks
	{	cout << setw(11) << "|";
		cout << setw(xcoord) << "*";
		cout << setw(10-xcoord) << " " << endl;
	}
}
	// note that my use of setw() is based on the 
                // assumption that it automatically alignstext within 
                // to the right. My comsc teach told me that though 
                // i could be doing it wrong.
Re: Graph a line, totally lost 80 80

If I understand you right, what you need to do is google for line drawing algos? In particular, Bresenham's line algorithm stands out.

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