Introduction

Hi everyone today we find the sum of N Natural Numbers in javascript. let's discuss how to solve this problem statement. if you want to check out yesterday's problem click here.

The goal is to use various techniques to get the sum of all the numbers that fall inside the specified interval given the range as integer input. To do this, we just repeat the base interval and end interval iterations while continuously increasing the number. Here are a few Javascript language solutions to the aforementioned issue.

• Method1: Using Brute Force

• Method2: Using the Formula

• Method3: Using Recursion

Method 1: Using Brute Force

In this method, we’ll use for loops to iterate through from the base interval to the upper interval meanwhile adding all the numbers to the sum variable.

Algorithm

• step 1: take input of a and b. a is starting number and b is the ending number

• step 2: take the sum variable and initialized it with zero

• Step 3: Initiate a for loop from the range [a,b].

• Step 4: Keep adding the value of the iterable variable to the sum variable.

• step 5: Print the sum variable.

Javascript Code

//Using Brute Force

let a = 5;
let b = 10;
let sum = 0;
for(let i=a;i<=b;i++){
  sum = sum + i;
}
console.log("The sum is "+ sum);

Output

The sum is 45

Method2: Using Formula

In this method, we’ll use a sequence and series formula to find the sum of n numbers in a series. Formula : N*(N+1)/2.

Algorithm

• step 1: Initialize num1 and num2

• step 2: Apply the given formula sum = b*(b+1)/2 – a*(a+1)/2 + a.

• step 3: Print the sum variable as the output.

Formula

sum = b*(b+1)/2 – a*(a+1)/2 + a.

Javascript Code

//Using formula
let num1 = 2;
let num2 = 5;
let sum = num2 * (num2 + 1) / 2 - num1 * (num1 + 1) / 2 + num1;
console.log("The Sum is " + sum);

Output

The Sum is 14

Method3: Using Recursion

In this method, we’ll use recursion to iterate through and sum up all the numbers that lay in the given interval.

Algorithm

• step 1: take input of a and b. a is starting number and b is the ending number

• step 2: take the sum variable and initialized it with zero.

• step 3: Define a recursive function with the base case as number1 == number2.

• step 4: Set the recursive set call as num1+ function(sum,num1+1,num2).

• step 5: print the returned value after calling the recursive functions.

Javascript Code

let a = 5;
let b = 10;

function getSum(sum, i, b) {
  if (i > b) {
    return sum;
  }
  return i + getSum(sum, i + 1, b);
}

console.log("The sum is " + getSum(0, a, b));

Output

The sum is 45

Conclusion

So this article we solved the problem statement using javascript language. I hope you found this article helpful for your web development journey.

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