JavaScript to print Floyd’s Triangle Pattern

In this post, I am will show you to write a simple JavaScript function to print Floyd’s Triangle pattern. If you don’t know what is Floyd’s Triangle, here is an explanation.

What is Floyd’s Triangle?

Floyd’s triangle is a right-angled triangular array of natural numbers, used in computer science education. It is named after Robert Floyd, who invented it in 1987. The first row contains a single number 1, and each subsequent row contains one more number than the previous row. The numbers are arranged in the triangle such that they form a sequence of consecutive natural numbers.

Here’s an example of Floyd’s triangle with 5 rows:

1
2 3
4 5 6
7 8 9 10
11 12 13 14 15

Now you know what is Floyd’s triangle, let us write the JavaScript program to print the same:

function floydsTriangle(n) {
  let num = 1;
  for (let i = 1; i <= n; i++) {
    for (let j = 1; j <= i; j++) {
      process.stdout.write(num + " ");
      num++;
    }
    console.log();
  }
}

floydsTriangle(5);

/*
Output:
1 
2 3 
4 5 6 
7 8 9 10 
11 12 13 14 15
*/