Write a program in C++ to convert a binary number to decimal number

#include <iostream>
#include <math.h>
using namespace std;
 
int main()
{
  long binaryNumber, decimalNumber = 0, j = 1, remainder;
	cout << "\n\n Convert a  binary number to decimal number:\n";
	cout << "-----------------------------------------------\n";
	cout << " Input a binary number: ";
	cin>> binaryNumber;
  while (binaryNumber != 0) 
  {
   remainder = binaryNumber % 10;
   decimalNumber = decimalNumber + remainder * j;
   j = j * 2;
   binaryNumber = binaryNumber / 10;
  }
  cout<<" The decimal number: " << decimalNumber<<"\n";
}