JavaScript: Convert Binary to Decimal using recursion

JavaScript Function: Exercise-11 with Solution

Binary to Decimal Conversion

Write a JavaScript program to convert binary number (positive) to decimal number using recursion.

Sample Solution-1:

JavaScript Code:

// Recursive function to convert a binary number to decimal
const binaryToDecimal = (binaryString, index = 0) => {
 // Base case: if the string is empty, return 0
 if (index === binaryString.length) {
 return 0;
 }
 // Get the current binary digit (0 or 1)
 const currentDigit = parseInt(binaryString[index]);
 // Recursive step: convert the rest of the string and update the result
 const restDecimal = binaryToDecimal(binaryString, index + 1);
 const currentDecimal = currentDigit * Math.pow(2, binaryString.length - index - 1);
 return currentDecimal + restDecimal;
};
// Test the function with different binary numbers
console.log(binaryToDecimal("1")); 
console.log(binaryToDecimal("0")); 
console.log(binaryToDecimal("10")); 
console.log(binaryToDecimal("101")); 

Output:

1
0
2
5

Flowchart:

Flowchart: JavaScript recursion function- Convert Binary to Decimal using recursion.

Live Demo:

See the Pen javascript-recursion-function-exercise-11 by w3resource (@w3resource) on CodePen.

Sample Solution-2:

JavaScript Code:

// Recursive function to convert a binary number to decimal
const binaryToDecimal = (binaryString, index = 0) => {
 // Base case: if the string is empty, return 0
 if (index === binaryString.length) {
 return 0;
 }
 // Get the current binary digit (0 or 1)
 const currentDigit = parseInt(binaryString[index]);
 // Recursive step: convert the rest of the string and update the result
 const restDecimal = binaryToDecimal(binaryString, index + 1);
 const currentDecimal = currentDigit * Math.pow(2, binaryString.length - index - 1);
 return currentDecimal + restDecimal;
};
// Test the function with different binary numbers
console.log(binaryToDecimal("1")); 
console.log(binaryToDecimal("0")); 
console.log(binaryToDecimal("10")); 
console.log(binaryToDecimal("101")); 

Output:

1
0
2
5

Flowchart:

Flowchart: JavaScript recursion function- Convert Binary to Decimal using recursion.

Live Demo:

See the Pen javascript-recursion-function-exercise-11 by w3resource (@w3resource) on CodePen.

For more Practice: Solve these Related Problems:

• Write a JavaScript function that converts a binary string to a decimal number recursively.
• Write a JavaScript function that recursively computes the decimal value of a binary number represented as a string.
• Write a JavaScript function that validates a binary string and then converts it to decimal recursively.
• Write a JavaScript function that implements binary to decimal conversion using recursion and handles leading zeros.

Improve this sample solution and post your code through Disqus.

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