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:

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:

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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