Python program to print a mirrored right-angle star triangle

Introduction:

In this post, we will learn how to print a mirrored right-angle triangle pattern in Python. For this example, I will use star (*) to print the pattern but you can also use any other character to print that.

The final output will look as like below:

	    *  
         *  *  
      *  *  *  
   *  *  *  *  
*  *  *  *  *

It looks complex but actually it is easy. Let me explain to you a bit more:

How to write the program:

Let’s take a look at the below pattern:

#  #  #  #  *  
#  #  #  *  *  
#  #  *  *  *  
#  *  *  *  *  
*  *  *  *  *

Can we print this ?

It’s height or size is 5
For row 1, we are printing 5 - 1 = 4 # and one *
For row 2, we are printing 5 - 2 = 3 # and two *
For row 3, we are printing 5 - 3 = 2 # and three *

Easy ?

So, if you print one blank space ’ ’ instead of ’#‘, you will get the above mirrored right angled triangle. Just write two loops and use the above logic 🙂

Using for loop:

Below is the program that uses for loop to print the mirrored right angled triangle pattern in python:

height = int(input("Enter the height of the triangle : "))

for i in range(1, height + 1):
    for j in range(1, height + 1):
        if(j <= height - i):
            print(' ', end = '  ')
        else:
            print('*', end = '  ')
    print()

We are taking the height of the triangle as input from the user and storing it in height variable.
We have two for loops. The outer loop is for the rows of the triangle and inner loop is for the columns of the triangle.
i is used for the outer loop and j is for the inner loop. We are checking if j is less than or equal to height - i, we are printing a blank space and else we are printing ***.

Sample Output:

Enter the height of the triangle : 5
            *  
         *  *  
      *  *  *  
   *  *  *  *  
*  *  *  *  *

Enter the height of the triangle : 10
                           *  
                        *  *  
                     *  *  *  
                  *  *  *  *  
               *  *  *  *  *  
            *  *  *  *  *  *  
         *  *  *  *  *  *  *  
      *  *  *  *  *  *  *  *  
   *  *  *  *  *  *  *  *  *  
*  *  *  *  *  *  *  *  *  *

Python program to print a Mirrored right angled triangle star pattern

Writing the same program using while loop:

height = int(input("Enter the height of the triangle : "))

i = 1

while(i < height + 1):
    j = 1
    while(j < height + 1):
        if(j <= height - i):
            print(' ', end = '  ')
        else:
            print('*', end = '  ')
        j = j + 1
    i = i + 1
    print()

This program is same as the previous one. The only difference is the place we are initializing the variables i and j.

Before starting the program, we are initializing i as 1.
In the outer while loop, we are initializing j as 1 before starting the inner while loop.

This program will print similar output.

CodeVsColor