How to find the largest of three numbers in JavaScript

In this Answer, we will discuss ways to find the largest of three numbers in JavaScript.

There are several methods that can be used to solve this problem, like using:

  • The if-else statement

  • The switch case statement

  • The math object Math.max()

Here, the if-else and switch case statements are conditional statements. These statements allow for different actions to be carried out based on various conditions.

The if-else statement

We can use the if-else statements to find the largest of three numbers. Let's see the code below.

Code example 1

// declaring the variables

let num1 = 30;

let num2 = 70;

let num3 = 15;

let largestNum;



if (num1 > num2 && num1 > num3) {

  largestNum = num1;

} 

else if (num2 > num1 && num2 > num3) {

  largestNum = num2;

} 

else {

  largestNum = num3;

}



console.log(largestNum);

Code explanation 1

Here is the explanation to the presented code.

  • Lines 2–4: Here, num1, num2, and num3 are declared, which represent the three numbers.

  • Line 5: The largestNum is initialized without any value.

  • Lines 7–9: We check if num1 is greater than num2 and num3. If this is true, then largestNum is assigned the value of num1.

  • Lines 10–12: We check if the first condition is not true; the code checks if num2 is greater than both num1 and num3. If this is true, then largestNum is assigned the value of num2.

  • Lines 13–15: We check if neither of the first two conditions are true. In this case, largestNum is assigned the value of num3.

  • Line 17: We print out the largest number.

The switch case statement

The switch case statements can also be used to solve this problem. Let's see the code below.

Code example 2

// declaring of variables
let num1 = 70;
let num2 = 40;
let num3 = 15;
let largestNum;
switch (true) {
  case num1 > num2 && num1 > num3:
    largestNum = num1;
    break;
  case num2 > num1 && num2 > num3:
    largestNum = num2;
    break;
  default:
    largestNum = num3;
}
console.log(largestNum);

Code explanation 2

Here is the explanation to the presented code.

  • Line 8: We use a switch statement with the expression (true) as the argument to determine which of the three variables, num1, num2, or num3, is the largest and assign that value to the largestNum variable.

  • Lines 9–10: The variables are compared using conditional statements (the > operator) to determine which of them is the largest. If num1 is the largest, its value is assigned to largestNum.

  • Lines 12–14: We check if num2 is the largest. If so, its value is assigned to largestNum.

  • Lines 15–16: If neither num1 nor num2 is the largest, then num3 is the largest and its value is assigned to largestNum.

The Math.max() method

The Math object allows us to perform mathematical tasks on numbers. The Math.max() method is a commonly used Math method that returns the highest value of a list.

Let's try this in the example below.

Code example 3

let num1 = 20;

let num2 = 70;

let num3 = 15;



let largestNum = Math.max(num1, num2, num3);



console.log("Three numbers are", num1, num2, "and", num3);

console.log("Largest of these numbers is", largestNum);

Code explanation 3

Here is the explanation to the presented code.

  • Lines 1–3: Here, num1, num2, and num3 are declared, and they represent the three numbers.

  • Line 5: The Math.max() method takes these three numbers as arguments and returns the largest number among them, which is assigned to the largestNum variable.

  • Lines 7–8: We print all three numbers and then the value of the largestNum variable.

New on Educative
Learn to Code
Learn any Language as a beginner
Develop a human edge in an AI powered world and learn to code with AI from our beginner friendly catalog
🏆 Leaderboard
Daily Coding Challenge
Solve a new coding challenge every day and climb the leaderboard

Free Resources

License: Creative Commons-Attribution NonCommercial-ShareAlike 4.0 (CC-BY-NC-SA 4.0)