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Thanks but I still get the same error plus this one ('RK1' : function does not take 0 parameters).
How can I declared it as static and making the call.
Regards,
Olagoke.
skg
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I didn't add the parameters (just used ()'s to indicate a function call).
You need to read an intro to C++ book since these questions show that you are a beginner (not bashing you, just letting you know that you will save yourself some time in the long run).
To declare something as static, you add <cdoe>static to its declaration.
static void func();
If you decide to become a software engineer, you are signing up to have a 1/2" piece of silicon tell you exactly how stupid you really are for 8 hours a day, 5 days a week
Zac
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#include <math.h>
#include <stdlib.h>
#include <stdio.h>
/*
n = Number of Links = 2
m1 = Mass of the First Link (The Annulus)
m2 = Mass of the Second Link
r1 = Inner Radius of Link 1 (The Annulus)
r2 = Outer Radius of Link 1 (The Annulus)
ra = Outer Radius of the Annulus
rb = Inner Radius of the Annulus
l = Half the Lenght of Link 1
d = Displacement from the Centre of Mass
g = Acceleration due to gravity = 9.81
t = time in seconds
*/
// Constants Declaration and initialization 42
const int n = 2;
const double m1 = 0.05;
const double m2 = 0.03;
const double h1 = 0.05;
const double h2 = 0.04;
const double r1 = 0.04;
const double r2 = 0.06;
const double ra = 0.04;
const double rb = 0.06;
const double l = 0.05;
const double d = 0.02;
const double g = 9.81;
const double h = 0.01;
//#define n (int) 2
//#define m1 (float) 0.05
//#define m2 (float) 0.03
//#define h1 (float) 0.03
//#define h2 (float) 0.04
//#define r1 (float) 0.04
//#define r2 (float) 0.06
//#define ra (float) 0.04
//#define rb (float) 0.06
//#define l (float) 0.05
//#define d (float) 0.02
//#define g (float) 9.81
//#define h (double) 0.01 70
// The Classes - Four in all.
class AngVel1 // For the first equation dQ1/dt = w1 (om1)
{
public:
double fn1 (double om1);
double RK1 (double v); // prototype for Runge-Kutta equation
private:
double InitialValue1;
};
// Function Definitions
double AngVel1 :: fn1 (double om1)
{
return om1;
}
double AngVel1 :: RK1(double v)
{
double k1,k2,k3,k4,l1,l2,l3;
k1 = h*fn1(v);
k2 = h*fn1(v + l1/2.0);
k3 = h*fn1(v + l2/2.0);
k4 = h*fn1(v + l3);
return v + (k1/6.0)+(k2/3.0)+(k3/3.0)+(k4/6.0);
};// End of Class AngVel1 101
class AngAccln1 // For the second equation, dw1/dt
{
public:
double fn2 (double t, double om1, double om2);
double RK2 (double x, double v, double p);
private:
double InitialValue3;
};
// Function Definition for Angular Acceleration
double AngAccln1 :: fn2 (double t, double om1, double om2)
{
double tau1, tetha1, tetha2;
tau1 = 0.1;
tetha1 = 0.5;
tetha2 = 06;
return (tau1 - 2*m2(r2*r2/4 -h2*h2/3 -d*d)*om1*om2*sin(tetha2)*cos(tetha2) - m2*g*d*cos(tetha1)*cos(tetha2))/
(m1(ra*ra + rb*rb)/4 + m1*h1*h1/3 + m2*r2*r2(1+sin(tetha2)*sin(tetha2))/4 + m2*h2*h2*cos(tetha2)*cos(tetha2)/3 + m2*d*d*cos(tetha2)*cos(tetha2));
}
double AngAccln1 :: RK2 (double x, double v, double p)
{
double l1,l2,l3,l4,k1,k2,k3;
l1 = h*fn2(x, v, p);
l2 = h*fn2(x + h/2.0, v + l1/2.0, p + k1/2.0);
l3 = h*fn2(x + h/2.0, v + l1/2.0, p + k2/2.0);
l4 = h*fn2(x + h, v + l3, p + k3);
return p + (l1/6.0)+(l2/3.0)+(l3/3.0)+(l4/6.0);
}; // End of Class AngAccln1 138
class AngVel2 // For the third equation dQ2/dt = w2 (om2)
{
public:
double fn3 (double om2);
double RK3 (double v); // prototype for Runge-Kutta equation
private:
double InitialValue2;
};
// Function Definitions 154
double AngVel2 :: fn3 (double om2)
{
return om2;
}
double AngVel2 :: RK3(double v)
{
double k1,k2,k3,k4,l1,l2,l3;
k1 = h*fn3(v);
k2 = h*fn3(v + l1/2.0);
k3 = h*fn3(v + l2/2.0);
k4 = h*fn3(v + l3);
return v + (k1/6.0)+(k2/3.0)+(k3/3.0)+(k4/6.0);
}; // End of class AngVel2
class AngAccln2 // For the second equation dw2/dQ 175
{
public:
double fn4 (double t, double om1);
double RK4 (double x, double p);
private:
double InitialValue4;
};
// Function Definition for Angular Acceleration of Link2
double AngAccln2 :: fn4 (double t, double om1)
{
double tau2, tetha1, tetha2;
tau2 = 0.1;
tetha1 = 0.5;
tetha2 = 0.6;
return (tau2 + m2(r2*r2/4 - h2*h2/3 - d*d)*om1*om1*sin(tetha2)*cos(tetha2) - m2*g*d*sin(tetha1)*sin(tetha2))/
m2(r2*r2/4 + h2*h2/3 + d*d);
}
double AngAccln2 :: RK4 (double x, double p)
{
double l1,l2,l3,l4,k1,k2,k3;
l1=h*fn4(x, p);
l2=h*fn4(x + h/2.0, p + k1/2.0);
l3=h*fn4(x + h/2.0, p + k1/2.0);
l4=h*fn4(x + h, p + k3);
return p + (l1/6.0)+(l2/3.0)+(l3/3.0)+(l4/6.0);
}; // End of Class AngAccln2
void main()
{
//RungeKutta rk = RungeKutta(0, 10, 0, 0.1);
// Open a file to save the results in
//ofstream of("rk_test.csv");
int i;
double init=1.0;
double temp1;
double temp2;
FILE *fp;
fp = fopen("data.txt", "w");
AngVel1 angvel;
angvel.RK1(init);
AngVel2 angvel2;
angvel2.RK3(init);
temp1 = angvel.RK1(init);
temp2 = angvel2.RK3(init);
printf("%4.4f \n", temp1);
printf("%4.4f \n", temp2);
//fprintf(fp, "%4.5f \n", temp);
for(i=1;i<50;i++){
temp1 = angvel.RK1(temp1);
temp2 = angvel2.RK3(temp2);
printf("%4.4f \n", temp1);
printf("%4.4f \n", temp2);
// fprintf(fp, "%4.5f \n", temp);
}
fclose(fp);
}
Dear Sac,
I am having these errors
C:\work\CPPCOACH\fintryy.cpp(124) : error C2064: term does not evaluate to a function
C:\work\CPPCOACH\fintryy.cpp(125) : error C2064: term does not evaluate to a function
C:\work\CPPCOACH\fintryy.cpp(125) : error C2064: term does not evaluate to a function
C:\work\CPPCOACH\fintryy.cpp(191) : error C2064: term does not evaluate to a function
C:\work\CPPCOACH\fintryy.cpp(192) : error C2064: term does not evaluate to a function
on the following lines of code
return (tau1 - 2*m2(r2*r2/4 -h2*h2/3 -d*d)*om1*om2*sin(tetha2)*cos(tetha2) - m2*g*d*cos(tetha1)*cos(tetha2))/
(m1(ra*ra + rb*rb)/4 + m1*h1*h1/3 + m2*r2*r2(1+sin(tetha2)*sin(tetha2))/4 + m2*h2*h2*cos(tetha2)*cos(tetha2)/3 + m2*d*d*cos(tetha2)*cos(tetha2));
and
return (tau2 + m2(r2*r2/4 - h2*h2/3 - d*d)*om1*om1*sin(tetha2)*cos(tetha2) - m2*g*d*sin(tetha1)*sin(tetha2))/
m2(r2*r2/4 + h2*h2/3 + d*d);
Thanks for your time.
Regards,
SKG!
skg
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Max is right - you have a stray semicolon after #define h. This causes this
k1 = h*fn1(y); to expand to
k1 = (double) 0.01;
*fn1(y); Newline inserted for clarity
Because of the relative precedence of the unary * and function call operators, this calls fn1 then tries to dereference the result. Because the return type of fn1 is double, which is not a pointer type, you get the error because you cannot dereference a double.
I'd also be wary of the precedence surrounding the cast operator. I'd put the macro definitions within extra parentheses, e.g.
#define n ((int) 2)
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// Simulation of the Dynamics of a 2-Link Pan-Tilt Robotic Manipulator
/* This programme calculates the Velocity, Acceleration and the angles of inclination
of the two links of the Spherical Pointing Motor, which is essentially a Two-Link Robotic
Manipulator*/
//#include <basis.h>
//#include <assert.h>
//#include <string.h>
//#include <iostream.h>
//#include <iomanip.h>
//#include <fstream.h>
// Precompiler Directives
#include <math.h>
#include <stdlib.h>
#include <stdio.h>
/*
n = Number of Links = 2
m1 = Mass of the First Link (The Annulus)
m2 = Mass of the Second Link
r1 = Inner Radius of Link 1 (The Annulus)
r2 = Outer Radius of Link 1 (The Annulus)
ra = Outer Radius of the Annulus
rb = Inner Radius of the Annulus
l = Half the Lenght of Link 1
d = Displacement from the Centre of Mass
g = Acceleration due to gravity = 9.81
t = time in seconds
*/
// Constants Declaration
#define n (int) 2
#define m1 (float) 0.05
#define m2 (float) 0.03
#define r1 (float) 0.04
#define r2 (float) 0.06
#define ra (float) 0.04
#define rb (float) 0.06
#define l (float) 0.05
#define d (float) 0.02
#define acc_due_gravity (float) 9.81
#define h (double) 0.01
// The Classes - Four in all.
class AngVel1 // For the first equation dQ1/dt
{
public:
AngVel1(); // Default Constructor
AngVel1(double om1); // The second and main constructor
double fn1 (double om1);
double RK1 (double y); // prototype for Runge-Kutta equation
private:
double InitialValue1;
};
// Function Definitions
double AngVel1 :: fn1 (double om1)
{
return om1;
}
double AngVel1 :: RK1(double y)
{
double k1,k2,k3,k4;
k1 = h*fn1(y);
k2 = h*fn1(y+(k1/2.0));
k3 = h*fn1(y+(k2/2.0));
k4 = h*fn1(y+k3);
return y+(k1/6.0)+(k2/3.0)+(k3/3.0)+(k4/6.0);
};
void main()
{
int i;
double init=1.0;
double temp;
FILE *fp;
fp = fopen("data.txt", "w");
temp = RK1(init);
printf("%4.4f \n", temp);
//fprintf(fp, "%4.5f \n", temp);
for(i=1;i<50;i++){
temp = RK1(temp);
printf("%4.4f \n", temp);
// fprintf(fp, "%4.5f \n", temp);
}
fclose(fp);
}
Thanks for your mail. I have corrected it and it work. Now, i've written the code further but I got this error ('RK1' : undeclared identifier ). How can this be resolved.
Also, do i need a constructor?
Thanks.
Regards,
SKG.
skg
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sahoong wrote: #define n (int) 2
#define m1 (float) 0.05
#define m2 (float) 0.03
#define r1 (float) 0.04
#define r2 (float) 0.06
#define ra (float) 0.04
#define rb (float) 0.06
#define l (float) 0.05
#define d (float) 0.02
#define acc_due_gravity (float) 9.81
#define h (double) 0.01;
Those should all be changed to const double or const float or const int.
If you decide to become a software engineer, you are signing up to have a 1/2" piece of silicon tell you exactly how stupid you really are for 8 hours a day, 5 days a week
Zac
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sahoong wrote:
#define m1 (float) 0.05
#define m2 (float) 0.03
#define r1 (float) 0.04
#define r2 (float) 0.06
#define ra (float) 0.04
#define rb (float) 0.06
#define l (float) 0.05
#define d (float) 0.02
#define acc_due_gravity (float) 9.81
#define h (double) 0.01;
While this has nothing to do with your actual problem, the typecasts are not necessary.
"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15
"Judge not by the eye but by the heart." - Native American Proverb
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as title. The code and the error messages are posted as follows. VS2005 + wtl. I checked some articles and references on polymorphism and operator overload, but haven't figured out the problems. So why it's wrong? How to correct it? Thanks in advance.
Basically the classes are used to query values (can be interpreted to different built-in types e.g. dword, char*, etc.) according to key.
Code: (you can copy it into your VC++ compiler and try)
-----
#include "stdafx.h" // wtl required
class ObjValue
{
};
class ObjKey
{
public:
class ObjValueProxy {
public:
ObjValue QueryValue() const;
operator ObjValue() const;
};
};
ObjValue ObjKey::ObjValueProxy::QueryValue() const
{
ObjValue* v = new ObjValue;
return *v;
// i don't care the value in this example
// in reality, it's the result of some query action
}
operator ObjKey::ObjValueProxy::ObjValue() const
{
return QueryValue();
}
Errors:
------
Compiling...
testoperatoroverloading.cpp
d:\test\testoperatoroverloading.cpp(25) : error C2039: 'ObjValue' : is not a member of 'ObjKey::ObjValueProxy'
d:\test\testoperatoroverloading.cpp(10) : see declaration of 'ObjKey::ObjValueProxy'
d:\test\testoperatoroverloading.cpp(26) : error C2270: '.?AVObjValue@@' : modifiers not allowed on nonmember functions
d:\test\testoperatoroverloading.cpp(26) : error C2801: 'operator ObjValue' must be a non-static member
d:\test\testoperatoroverloading.cpp(27) : error C3861: 'QueryValue': identifier not found
test - 4 error(s), 0 warning(s)
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Try this:
class ObjValue
{
int i;
};
class ObjKey
{
public:
class ObjValueProxy {
public:
ObjValue QueryValue() const;
operator ObjValue() const {return QueryValue();}
};
};
ObjValue ObjKey::ObjValueProxy::QueryValue() const
{
ObjValue* v = new ObjValue;
return *v;
}
Memory leak...
ObjValue* v = new ObjValue;
return *v;
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right... i haven't paid attention to the memory leak since it was created to reproduce the problem in my real project...
i know it would compile in the way you proposed, but i prefer putting them outside in a separate .cpp file. and! reason has actually been found out! The correct form should be
ObjKey::ObjValueProxy::operator ObjValue() const
instead of
operator ObjKey::ObjValueProxy::ObjValue() const
Thanks anyway!
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Cool! 
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I am porting an application from Win2000 to WINXP using visual studio 2005 standard edition. I am calling the network functions: WNetCancelConnection2 and WNetAddConnection2. I have attached a code snippet. The drive maps and unmaps correctly. No errors are returned when the functions are called. However, if I remap a drive with the same letter to a different server, the windows explorer label is not updated. It displays the old server name. If I click on properties, it shows the correct server. This works correctly in Win2000. I am mapping to unix servers running PC Net Link or SAMBA. Anyone seen this issue. Any suggestions on what to do.
----------------------------------------
Code snippet:
CMapDialog dlg;
if( dlg.DoModal() == IDOK )
{
CWaitCursor cWaitCursor;
DWORD dwStatus= WNetCancelConnection2(strDriveLetter, CONNECT_UPDATE_PROFILE, TRUE);
m_strCurrentMapping = _T("Unmapped");
if( dlg.GetMap() )
{
CString strShare(dlg.GetShareName());
NETRESOURCE nr;
nr.dwType = RESOURCETYPE_ANY;
nr.lpLocalName = strDriveLetter;
nr.lpRemoteName = strShare.GetBuffer(256);
nr.lpProvider = NULL;
if( (dwStatus = WNetAddConnection2(&nr, NULL, NULL, CONNECT_UPDATE_PROFILE)) == NO_ERROR )
{
strErrorText.Format(IDS_MAP_OK, strDriveLetter, strShare);
OutputToEvents(strErrorText, INFO);
}
else
{
strErrorText.Format(IDS_MAP_ERROR, strDriveLetter, GetLastError(), GetLastErrorText());
OutputToEvents(strErrorText, FATAL);
}
m_strCurrentMapping = GetMapString();
}
UpdateMapString();
}
}
}
Fred Shaw
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fred shaw wrote: However, if I remap a drive with the same letter to a different server, the windows explorer label is not updated. It displays the old server name.
What happens if you try and access that server? Does WE try the older server or the new one?
"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15
"Judge not by the eye but by the heart." - Native American Proverb
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It accesses the new server, however the old server name is being displayed which is wrong since it is pointing to the new server.
Fred Shaw
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I have subclassed a few controls (the win32 method not MFC) and am now trying to prevent flickering while the control is being moved around the main window. Basically, all I want to do is prevent the control from painting itself while the main window is being resized. I am able to trap the WM_MOVE message, but unable to trap the WM_ENTERSIZEMOVE or WM_EXITSIZEMOVE messages. I'm guessing these are only sent to the top level window. Can anybody suggest an alternative to determining when a control starts moving and ends moving?
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It sounds like the entire client area of the background window is being repainted every time
a WM_PAINT occurs.
In the window's WM_PAINT handler if you are not using BeginPaint() you can make a clipping
region to only draw the newly exposed part of the window using GetUpdateRect (make sure you
validate the rect with ValidateRect() so you don't get repeated WM_PAINT messages for the same
rect).
Or maybe it's happening in a WM_ERASEBKGND handler in the window or control
Mark
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Mark Salsbery wrote: Or maybe it's happening in a WM_ERASEBKGND handler in the window or control
Both the main window and the control have a bitmap skin applied to them. For the main window, each time it is resized I must rebuild the bitmap used for the skin and repaint it to the window. This is naturaly done in the WM_ERASEBKGND handler.
I will have a play with the clipping region and see if I can better the performance a little.
A simple hack I came up with is to draw the child controls image to the main windows image. The flickering is still there, but cannot be seen.
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Does using the WS_CLIPCHILDREN style on the main window help at all?
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I have to access tables from MicroSoft Access and read write its contents.
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sujeet_kulk wrote: I have to access tables from MicroSoft Access and read write its contents.
OK?  What specifically did you want to know?
"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15
"Judge not by the eye but by the heart." - Native American Proverb
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I have to change(/read) data in Microsoft Access Tables (data base tables) through Automation( using object model of MS Access (not through ODBC)) in MFC.
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sujeet_kulk wrote: I have to change(/read) data in Microsoft Access Tables (data base tables) through Automation( using object model of MS Access (not through ODBC)) in MFC.
I got that much from your initial post. What you are asking, however, is very broad. It can't be answered in a simple post.
Do you need to add Access' type library to your project?
"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15
"Judge not by the eye but by the heart." - Native American Proverb
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No I have added that, atleast name the classes and methods involved and sequence if possible.
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sujeet_kulk wrote: ...name the classes and methods involved...
They are in the .h and .cpp files that were added to your project. The first one you'll need is _Application. Call its CreateDispatch() method.
"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15
"Judge not by the eye but by the heart." - Native American Proverb
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Fine with that but how to get the rows and columns of a datatable, I mean which are the classes.
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