JavaScript Program to Print Reverse Floyd Pattern Triangle Pyramid

Printing a reverse Floyd pattern triangle pyramid involves outputting a series of numbers in descending order, forming a triangular shape with each row containing one less number than the previous row. The numbers are arranged in such a way that they form a right-angled triangle, reminiscent of Floyd’s triangle, but in reverse order.

Example:

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

These are the following approaches:

Approach 1: Using nested Loop

Using nested loops, iterate from the specified number of rows downwards, printing numbers in descending order for each row, forming a reverse Floyd pattern triangle pyramid.

Example: The function myFunction generates a reverse Floyd pattern triangle pyramid by iterating through rows downwards, printing descending numbers, and forming a triangle with decreasing lengths per row.

Javascript

function myFunction(rows) {
    let num = rows * (rows + 1) / 2;
    for (let i = rows; i >= 1; i--) {
        let pattern = '';
        for (let j = 1; j <= i; j++) {
            pattern += num-- + ' ';
        }
        console.log(pattern);
    }
}

myFunction(5);

Output

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

Approach 2: Using Recursion

The recursion approach recursively prints a reverse Floyd pattern triangle pyramid. It decreases the number of rows in each call, printing descending numbers per row until reaching the base case of zero rows.

Example: The function myFunction recursively generates a reverse Floyd pattern triangle pyramid. It decreases rows in each call, printing descending numbers per row until reaching zero rows.

Javascript

function myFunction(rows, num = rows
    * (rows + 1) / 2) {
    if (rows === 0) return;
    let pattern = '';
    for (let i = 1; i <= rows; i++) {
        pattern += num-- + ' ';
    }
    console.log(pattern);
    myFunction(rows - 1, num);
}

myFunction(6);

Output

21 20 19 18 17 16 
15 14 13 12 11 
10 9 8 7 
6 5 4 
3 2 
1