JavaScript: Calculate the sum of n + n/2 + n/4 + n/8 + ....

JavaScript Basic: Exercise-113 with Solution

Sum n + n/2 + n/4 + ...

Write a JavaScript program to calculate the sum of n + n/2 + n/4 + n/8 + .... where n is a positive integer and all divisions are integers.

Visual Presentation:

Sample Solution:

JavaScript Code:

// Function to calculate the sum of integers from 1 to num using bitwise operation
function int_sum(num) {
    var s_sum = 0; // Initialize the sum variable
    while (num > 0) { // Loop until num is greater than 0
        s_sum += num; // Add num to the sum
        num = Math.floor(num / 2); // Divide num by 2 using floor division
    }
    return s_sum; // Return the sum of integers from 1 to num
}

// Examples to calculate the sum of integers from 1 to the given number
console.log(int_sum(8));  
console.log(int_sum(9));  
console.log(int_sum(26)); 

Output:

15
16
49

Live Demo:

See the Pen javascript-basic-exercise-113 by w3resource (@w3resource) on CodePen.

Flowchart:

ES6 Version:

// Function to calculate the sum of integers from 1 to num using bitwise operation
const int_sum = (num) => {
    let s_sum = 0; // Initialize the sum variable
    while (num > 0) { // Loop until num is greater than 0
        s_sum += num; // Add num to the sum
        num = Math.floor(num / 2); // Divide num by 2 using floor division
    }
    return s_sum; // Return the sum of integers from 1 to num
}

// Examples to calculate the sum of integers from 1 to the given number
console.log(int_sum(8));  
console.log(int_sum(9));  
console.log(int_sum(26));  

For more Practice: Solve these Related Problems:

• Write a JavaScript program that computes the sum of the series n + floor(n/2) + floor(n/4) + ... until the term becomes 0.
• Write a JavaScript function that iteratively adds the result of integer division of n by powers of 2 until no further division is possible.
• Write a JavaScript program that calculates the cumulative sum of n divided by successive powers of 2, ensuring integer division at each step.

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