C / C++ / MFC

Ahmed Ismail Mohamed wrote:

I want to know is it possible to to make a constant variable to hold a value the user of my application at the run of the program choose

Ahmed Ismail Mohamed wrote:

and i want him to not not chang it again.

#include <iostream>

using namespace std;
class CCTest {
public:
   void setNumber( int );
   void printNumber() const;
private:
   int number;
};

void CCTest::setNumber( int num ) { number = num; }

void CCTest::printNumber() const {
   cout << "\nBefore: " << number;
   const_cast< CCTest * >( this )->number--;
   cout << "\nAfter: " << number;
}

int main() {
   CCTest X;
   X.setNumber( 8 );
   X.printNumber();
}

Regards

LateNightsInNewry wrote:

I still do not understand what it was all about

LateNightsInNewry wrote:

this will introduce the poser of the question to the English Language

Regards

Nader Elshehabi wrote:

I believe he was asking about casting a const variable to remove its constancy

const int var_name (const int var_val = 0)<br />
{<br />
    static const int var = var_val;<br />
    return var;<br />
}

var_name (temp1); // set const value<br />
temp3 = var_name (temp2); // no effect of temp2; temp3 == temp1

MayankT wrote:

but it is expensive

MayankT wrote:

one more advantage is that this way it is much more difficult to use a pointer and modify the value.

Regards

Nader Elshehabi wrote:

What's the difference between declaring a variable as a class member or as a static in a function in a class??

Nader Elshehabi wrote:

You can change temp3 to whatever you want after the call.

Nader Elshehabi wrote:

scenario where we should use this approach

Nader Elshehabi wrote:

I hope you don't mean reverse engineering?

FILE *infile;
if ((infile = _tfopen(sFilename,_T("rb") )) == NULL) {
    return FALSE;
}

// obtain file size.
fseek(infile , 0 , SEEK_END);
long lSize = ftell(infile);
rewind(infile);

//read in the contents of the input file
char* pszIn = new char[lSize];
fread(pszIn,1,lSize,infile);
fclose(infile);