C++ Programming Code Examples C++ > Conversions Code Examples C++ Program to Convert Binary Number to Decimal and vice-versa C++ Program to Convert Binary Number to Decimal and vice-versa In this example, you will learn to convert binary number to decimal, and decimal number to binary manually by creating user-defined functions. #include <iostream> #include <cmath> using namespace std; int convertBinaryToDecimal(long long); int main() { long long n; cout << "Enter a binary number: "; cin >> n; cout << n << " in binary = " << convertBinaryToDecimal(n) << "in decimal"; return 0; } int convertBinaryToDecimal(long long n) { int decimalNumber = 0, i = 0, remainder; while (n!=0) { remainder = n%10; n /= 10; decimalNumber += remainder*pow(2,i); ++i; } return decimalNumber; }