A Python program to print the pattern of a Right angled triangle

We already know  the shape of a right angled triangle. So to print the pattern of that triangle with a specific character here we go.

Pattern program of Right angled triangle

num=int(input("Enter the number of rows to print: "))
for x in range(1,num+1):
    for y in range(1,x+1):
        print("*", end= " ")
    print( )

Output

Enter the number of rows to print: 5
* 
* * 
* * * 
* * * * 
* * * * *

Tracing:

Let’s trace the above program step by step.

1. for x=1 in range(1,5+1) ⇒range(1,6) ⇒True then execution moves to next for loop; for y=1 in range(1,1+1) ⇒ range(1,2) ⇒True. Then it moves to immediate statement(i.e print(“*”) statement) and prints “*”. Here it prints one “*” because of range (1,2) is 1.

2. Similarly, for x=2 in range(1,5+1) ⇒range(1,6) ⇒True then, for y=2 in range(1,2+1) ⇒ range(1,3) ⇒True.Range(1,3) is 2 and it prints “**”.

3. for x=3 in range(1,5+1) ⇒range(1,6) ⇒True then, for y=3 in range(1,3+1) ⇒ range(1,4) ⇒True.Range(1,4) is 3and it prints “***”.

4.for x=4 in range(1,5+1) ⇒range(1,6) ⇒True then, for y=4 in range(1,4+1) ⇒ range(1,5) ⇒True.Range(1,5) is 4 and it prints “****”.

5.for x=5 in range(1,5+1) ⇒range(1,6) ⇒True then, for y=5 in range(1,5+1) ⇒ range(1,6) ⇒True.Range(1,6) is 5 and it prints “*****”.

6.for x=6 in range(1,6+1) ⇒range(1,7) ⇒6(False) because the input range is given as ‘5’.Hence it exits from the inner for loop and executes the outer for loop print statement which has nothing to print.

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