Page 319 - Computer Science V2.0 Class 11

17 nSpaces = nSpaces - 1
18 nSymbols = nSymbols + 2
>>> isoscelesTriangle(6,"*")

Sample Output:
*
***
*****
*******
*********
***********
Fig 11.7 : Isosceles Triangle

11.7.1 Power Drum
Having learnt, how to display an inverted isosceles triangle (program 11.13) and an isosceles triangle (Program 11.14),
to display a power drum we just need to invoke these functions. For example, to display a power drum of asterisks
comprising 12 rows, we need to display an inverted isosceles triangle, followed by an isosceles triangle, each comprising
six rows. Note that the number of rows in a power drum is always even.

Program 11.15 Write a function powerDrum(nRows,symbol) to display the power drum pattern of a symbol.

01 def powerDrum(nRows, symbol):
02 '''
03 Objective: To display an power drum pattern
04 Inputs:
05 nRows : number of rows
06 symbol: symbol to be used in the pattern
07 Return value: None
08 '''
09 #Approach: Ensure nRows is even
10 #Invoke functions invertedIsoTriangle,isoscelesTriangle
11 assert nRows%2==0, 'A power drum must have even no of rows'
12 invertedIsoTriangle(nRows//2, symbol)
13 isoscelesTriangle(nRows//2, symbol)
>>> powerDrum(12,'*')
Sample Output:

***********
*********
*******
*****
***
*
*
***
*****
*******
*********
***********
Fig 11.8: Power Drum
11.7.2 Diamond
To display a diamond, it would be tempting to invoke the functions isoscelesTriangle() and
invertedIsoTriangle(). We first display the isosceles triangle and then the inverted isosceles triangle
(see Fig 11.9).

Looping in Python 305