binary to decimal

/* C++ program to convert binary number into decimal */
 #include <iostream>
     using namespace std;
 int main()
 {
     long bin, dec = 0, rem, num, base = 1;
     cout << "Enter the binary number(1s and 0s) : ";
     cin >> num;
     bin = num;
     while (num > 0)
     {
         rem = num % 10;
         dec = dec + rem * base;
         base = base * 2;
         num = num / 10;
     }
     cout << "The decimal equivalent of " << bin << " : " << dec << endl;
     return 0;
 }