Create a MFC project named osci and choose SDI "Single Document" Maximized

Open file osciView.cpp and search:

void CosciView::OnDraw(CDC* /*pDC*/)

Change this line into:

void CosciView::OnDraw(CDC* pDC)

info: with VisualC++ 6.0 this line needs no change

Add code to have the same function as below

Compile and see the axis

void CosciView::OnDraw(CDC* pDC)
{
	CosciDoc* pDoc = GetDocument();
	ASSERT_VALID(pDoc);
	if (!pDoc)
		return;
	// TODO: add draw code for native data here
#define x0 50
#define y0 400

        pDC -> MoveTo(x0,y0);				  // X axis	
	pDC -> LineTo(x0+1000,y0);

	pDC -> MoveTo(x0,y0 - 300);			 // Y axis
	pDC -> LineTo(x0,y0 + 300);

	// ==>>  code 01	
}

open the file osciDoc.cpp

insert the variable iFilesize and cBuffer

info: these are global variables

// osciDoc.cpp : implementation of the CosciDoc class
#include "stdafx.h"
#include "osci.h"
#include "osciDoc.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#endif

unsigned int iFileSize;
char cBuffer[100000];

now insert the code in function: Serialize

insert only one line

void CosciDoc::Serialize(CArchive& ar)
{
	if (ar.IsStoring())
	{
		// TODO: add storing code here
	}
	else
	{
		// TODO: add loading code here
		iFileSize = ar.Read(cBuffer,100000);
	}
}

Have you tested the program ? Everthing okay?

In the file osciView.cpp we declare the same variables as in osciDoc.cpp, but as extern

we need some more variables.
info: you can declare all as class variables in the header files, but
we take the simplest way and use global variables

// osciView.cpp : implementation of the CosciView class
//

#include "stdafx.h"
#include "osci.h"

#include "osciDoc.h"
#include "osciView.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#endif

#define LF 0x0A 
extern unsigned int iFileSize;
extern char cBuffer[];
char *ptr1,*ptr2;
float fosciValue;
int xx,yy;
int ii;

Now we extend the code in function OnDraw

info: if the cBuffer is empty then iFilesize has the value zero and we return;
otherwise, we set the pointer ptr1 at the beginning of cBuffer and ptr2 at the end

	// ==>>  code 01	
	if(iFileSize == 0) return;
	ptr1     = cBuffer;
	ptr2     = ptr1 + iFileSize;	
	// ==>>  code 02	

We skip the first 4 lines

info: as long as the value of pointer ptr1 is not equal LineFeed, ptr1 is incremented
at last ptr1 must be incremented to skip LF

	// ==>>  code 02
	ii=4;
	while(ii--) 			// skip the first 4 lines
	{ 
	while(*ptr1 != LF ) ptr1++;	// search Line Feed
	ptr1++;				// skip Line Feed
        } 
	// ==>>  code 03
	

Now we can insert the line scan code and draw the osci data

info: first we set the pen with MoveTo onto the origin of the axis
we set the X-Axis index xx to zero
we remain in the loop until ptr1(beginning of cBuffer) is lower than ptr2 (end of cBuffer)
The function sscanf is a very old C function and always works very well.
Multiply with a factor and then the value is saved as integer into the variable yy
Now we can draw with LineTo a line from the last point
As there are too many data we always skip 10 lines

	// ==>>  code 03
	pDC -> MoveTo(x0,y0);	
	xx=0;
	while(ptr1 < ptr2)
	{
	sscanf(ptr1,"%f",&fosciValue);
    	fosciValue *= 200;
	yy = (int)fosciValue;
	pDC->LineTo(x0+xx,y0 - yy); xx++;

	ii=10;
	while(ii--) {	while(*ptr1 != LF ) ptr1++;   ptr1++; } // skip 10 lines
	}	

control Your OnDraw

If everything is okay, start the program and open the file TEK00000.DAT

void CosciView::OnDraw(CDC* pDC)
{
	CosciDoc* pDoc = GetDocument();
	ASSERT_VALID(pDoc);
	if (!pDoc)
		return;
	// TODO: add draw code for native data here
#define x0 50
#define y0 400

        pDC -> MoveTo(x0,y0);				  // X axis	
	pDC -> LineTo(x0+1000,y0);

	pDC -> MoveTo(x0,y0 - 300);			  // Y axis
	pDC -> LineTo(x0,y0 + 300);
		
	// ==>>  code 01
	if(iFileSize == 0) return;
	ptr1     = cBuffer;
	ptr2     = ptr1 + iFileSize;
	// ==>>  code 02

	ii=4;
	while(ii--) {	while(*ptr1 != LF ) ptr1++;   ptr1++; } // skip the first 4 lines

	// ==>>  code 03
	pDC -> MoveTo(x0,y0);	
	xx=0;
	while(ptr1 < ptr2)
	{
	sscanf(ptr1,"%f",&fosciValue);
    	fosciValue *= 200;
	yy = (int)fosciValue;
	pDC->LineTo(x0+xx,y0 - yy); xx++;

	ii=10;
	while(ii--) {	while(*ptr1 != LF ) ptr1++;   ptr1++; } // skip 10 lines
	}
}