Related Articles

# Recursive Program for Binary to Decimal

• Difficulty Level : Easy
• Last Updated : 28 May, 2021

Given a binary number as string, find its decimal equivalent.
Examples:

```Input :  binary = "101"
Output :   5

Input :  binary = "1111"
Output :   15```

We have discussed iterative solution to convert Binary to Decimal.
The idea is simple, we add current term and recur for remaining terms.

## C++

 `// Recursive CPP program to convert binary``// decimal``#include``using` `namespace` `std;` `int` `toDecimal(string binary, ``int` `i=0)``{``    ``// If we reached last character``    ``int` `n = binary.length();``    ``if` `(i == n-1)``      ``return` `binary[i] - ``'0'``;``    ` `    ``// Add current tern and recur for``    ``// remaining terms``    ``return` `((binary[i] - ``'0'``) << (n-i-1))  +``            ``toDecimal(binary, i+1);``}` `// Driver code``int` `main()``{``    ``string binary = ``"1010"``;``    ``cout << toDecimal(binary) << endl;``    ``return` `0;``}`

## Java

 `// Recursive Java program to convert binary``// decimal`  `class` `GFG``{``    ``static` `int` `toDecimal(String binary,``int` `i)``    ``{``        ``// If we reached last character``        ``int` `n = binary.length();``        ``if` `(i == n-``1``)``        ``return` `binary.charAt(i) - ``'0'``;``        ` `        ``// Add current tern and recur for``        ``// remaining terms``        ``return` `((binary.charAt(i) - ``'0'``) << (n-i-``1``)) +``                ``toDecimal(binary, i+``1``);``    ``}``    ` `    ``// Driver code``    ``public` `static` `void` `main(String []args)``    ``{``        ``String binary = ``"1010"``;``        ``int` `i=``0``;``        ``System.out.println(toDecimal(binary,i));``        ` `    ``}` `}` `// This code is contributed``// by ihritik ( Hritik Raj)`

## Python3

 `# Recursive Python3 program to convert``# binary decimal` `def` `toDecimal(binary, i ``=` `0``):` `    ``# If we reached last character``    ``n ``=` `len``(binary)``    ``if` `(i ``=``=` `n ``-` `1``) :``        ``return` `int``(binary[i]) ``-` `0``    ` `    ``# Add current tern and recur for``    ``# remaining terms``    ``return` `(((``int``(binary[i]) ``-` `0``) << (n ``-` `i ``-` `1``)) ``+``                        ``toDecimal(binary, i ``+` `1``))` `# Driver code``if` `__name__ ``=``=` `"__main__"` `:``    ` `    ``binary ``=` `"1010"``    ``print``(toDecimal(binary))` `# This code is contributed by Ryuga`

## C#

 `// Recursive C# program to convert binary``// decimal`  `using` `System;``class` `GFG``{``    ``static` `int` `toDecimal(``string` `binary, ``int` `i=0)``    ``{``        ``// If we reached last character``        ``int` `n = binary.Length;``        ``if` `(i == n-1)``        ``return` `binary[i] - ``'0'``;``        ` `        ``// Add current tern and recur for``        ``// remaining terms``        ``return` `((binary[i] - ``'0'``) << (n-i-1)) +``                ``toDecimal(binary, i+1);``    ``}``    ` `    ``// Driver code``    ``public` `static` `void` `Main()``    ``{``        ``string` `binary = ``"1010"``;``        ``Console.WriteLine(toDecimal(binary));``        ` `    ``}` `}` `// This code is contributed``// by ihritik ( Hritik Raj)`

## PHP

 ``

## Javascript

 ``
Output:
`10`

Attention reader! Don’t stop learning now. Get hold of all the important DSA concepts with the DSA Self Paced Course at a student-friendly price and become industry ready.  To complete your preparation from learning a language to DS Algo and many more,  please refer Complete Interview Preparation Course.

In case you wish to attend live classes with experts, please refer DSA Live Classes for Working Professionals and Competitive Programming Live for Students.

My Personal Notes arrow_drop_up