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-   -   [C++] Need help with win32 program (http://www.go4expert.com/forums/cpp-help-win32-program-t13799/)

thekevin07 13Sep2008 11:18

[C++] Need help with win32 program
 
I need to graph 3 points based on the linear or quadratic equation and I can't get my head around how to graph the points. It will work fine if you put points in that are in sequence like 2 3 4 but not 2 4 5 any help is greatly appreciated below is the source from microsoft visual studio 2008

Code:

// program002.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <cstdio>
#include <cmath>

using namespace std;

int _tmain(int argc, _TCHAR* argv[])
{

        int iNumOfDataPoints, iEquation;
        double mx, my;


        //linear or quadratic if the user enters 0 or any other number the program assums quadratic
        cout << "Choose an equation: Enter 1 for Linear and 0 for quadratic (default is quadratic)" << endl;
        cin >> iEquation;


        //ask user how many data points
        cout<<"Please enter your number from lowest to highest."<<endl;
        cout << "How many data points would you like to plot (max 3)?" << endl;
        cin >> iNumOfDataPoints;
       
        double iDataX[4], iDataY[4];
       
        for(int c=1;c<=iNumOfDataPoints;c++)
        {
                cout << "Enter data point(x) ";
                cout <<        c << endl;
                cin >> iDataX[c];

                if(iDataX[c]<=0)
                {
                        cout << "Data point must be positive number. " << endl;
                        return 0;
                }

                //now lets get the y values
                //linear
                if(iEquation==1)
                {
                        iDataY[c]= 2*iDataX[c] + 4;
                }
                else //quadratic
                {
                        iDataY[c]= pow(iDataX[c],2) + 4*iDataX[c]+2;
                }
        }

        cout << endl;
        for(int c=1;c<=iNumOfDataPoints;c++)
        {
                cout << iDataY[c] << endl;
        }
       
cout << endl;
cout << endl;
        //find largest value
       
        mx=std::max(iDataX[1],iDataX[2]);
        mx=std::max(mx,iDataX[3]);
        double mx2=mx;
       
       

        my=std::max(iDataY[1],iDataY[2]);
        my=std::max(my,iDataY[3]);

       

//graph
        int z=iNumOfDataPoints;

        for(my;my!=0;my--)
        {
                cout<<"|";
                if(my==iDataY[z])
                {
                                if(mx==iDataX[z])
                                {
                                        int n=1;
                                        while(n<mx)
                                        {
                                                cout<<" ";
                                                n++;
                                        }
                                        cout<<"*"<<endl;
                                        z--;
                                }
                                else
                                {
                                        cout<<endl;
                                }
                                mx--;
                }
                else
                {
                        cout<<endl;
                }
        }
       

        for(int f=0;f<=mx2;f++)
        {
                cout << "-";
        }
        cout << endl;
       


        return 0;
}


xpi0t0s 14Sep2008 15:13

Re: [C++] Need help with win32 program
 
Just change
if(mx==iDataX[z])
to
mx=iDataX[z];
and lose the else clause.

You don't need an if at this point because if(my==iDataY[z]) already removes all cases where there isn't a * to plot. So all you need to do within this if is to look up the value of iDataX[z] and draw the * in the appropriate place.

xpi0t0s 14Sep2008 15:16

Re: [C++] Need help with win32 program
 
You also don't need the mx--. It was this that was making it "work" when the entered values were consecutive. Consequently you also don't need mx2 as mx doesn't change over the output loop.

oogabooga 14Sep2008 23:50

Re: [C++] Need help with win32 program
 
Just a small correction to xpi0t0s's analysis of your code. mx does change during the output loop because you are assigning to it (in the fixed version). So you do still need mx2.

By the way, you should get used to using zero-based array subscripting, since that is the C/C++ way.

thekevin07 15Sep2008 06:03

Re: [C++] Need help with win32 program
 
Thank you works perfectly now


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