Page 318 - Computer Science V2.0 Class 11

Program 11.13 To display the inverted isosceles triangular pattern of a symbol.

01 def invertedIsoTriangle(nRows, symbol):
02 '''
03 Objective: To display an inverted isosceles triangular pattern
04 Inputs:
05 nRows : number of rows
06 symbol: symbol to be printed
07 Return value: None
08 '''
09 #Approach: In each line,
10 # first print enough blanks, then enough symbols
11
12 nSpaces = 0
13 nSymbols = 2 * nRows - 1
14
15 for i in range(nRows):
16 print(' ' * nSpaces, end = '')
17 print(symbol * nSymbols)
18 nSpaces = nSpaces + 1
19 nSymbols = nSymbols - 2
20 invertedIsoTriangle(6, '*')

Sample Output:
***********
*********
*******
*****
***
*
Fig 11.6: Inverted Isosceles Triangle
Next, let us write a function to print an isosceles triangle using a given symbol (say, symbol). Fig 11.7 shows an
isosceles triangle comprising six rows using asterisks. Note that the last row (6 row) does not have any leading
th
spaces, 5 row has one leading space, the 4 row has two leading spaces, and so on. Finally, the first row has 5 (=6-1)
th
th
spaces. Thus, i row has nRows-i leading spaces. Furthermore, the first row has one asterisk, the second row has
th
th
3 asterisks, and so on. Finally, the sixth row has 11 (=6×2-1) asterisks. Thus, i row has 2×i-1 asterisks. Now we are
ready to write a function to display an isosceles triangle.
Program 11.14 Write a function isoscelesTriangle(nRows,symbol) to display the isosceles triangular pattern
of a symbol.

01 def isoscelesTriangle(nRows, symbol):
02 '''
03 Objective: To display an isosceles triangular pattern of a symbol
04 Inputs:
05 nRows : number of rows
06 symbol: symbol to be printed
07 Return value: None
08 '''
09 #Approach: In each line,
10 # first print enough blanks, then enough symbols
11
12 nSpaces = nRows-1
13 nSymbols = 1
14 for row in range(1, nRows + 1):
15 print(' ' * nSpaces, end = '')
16 print(symbol * nSymbols)

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