In this tutorial, we will write a program to convert a binary number into decimal in C++. Before that, you must have knowledge of the following topics in C++.

**Binary number**

The binary numbers are based on 0 and 1, so it is a base 2 number. They are the combination of 0 and 1. For example, 1001, 110101, etc.

**Decimal Number**

These are the numbers with a base of 10, which ranges from 0 to 9. These numbers are formed by the combination of 0 to 9 digits such as 24, 345, etc.

Here is the chart where for the equivalent value of decimal and binary numbers.

Now let us go through a program for the conversion of binary to decimal in C++.

**C++ Program to Convert Binary to Decimal**

The program asks the user to enter a binary number and using a while loop it calculates the decimal value. Lastly, display the equivalent decimal value.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 | #include <iostream> using namespace std; int main() { int bin, deci = 0, i = 1, rem; cout << "Enter a Binary Number: "; cin >> bin; while (bin != 0) { rem = bin % 10; deci = deci + (rem *i); i = i * 2; bin = bin / 10; } //Display the equivalent decimal number cout << "Decimal Value: " << deci; return 0; } |

**Output:**

`Enter a Binary Number: 1010`

Decimal Value: 10

Also, check out a similar program: