Using the const variable modifier in C++ program to declare the constant variable


Compiler: Visual C++ Express Edition 2005

Compiled on Platform: Windows XP Pro SP2

Header file: Standard

Additional project setting: Set project to be compiled as C++

Project -> your_project_name Properties -> Configuration Properties -> C/C++ -> Advanced -> Compiled As: Compiled as C++ Code (/TP)

Other info:

To do: Declaring and using the constant variable in C++ programming



To show: The const usage in C++ program declaring constant variable


// Demonstrates type casting

#include <iostream>

using namespace std;


double funct1(double& f)


// do some work here...


cout<<"f = "<<f<<endl;

// return the incremented value...

return f;



// const argument, can't be modified...

void funct2(const double& d)


cout<<"d = "<<d<<endl;

// remove const...

// use the non-const argument, making function call...

double value = funct1(const_cast<double> (d));

// display the returned value...

cout<<"value = "<<value<<endl;



int main(void)


double c = 4.324;


// first function call...



return 0;



Output example:


d = 4.324

f = 5.324

value = 5.324

Press any key to continue . . .



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