Iterations Code

• Please solve the following questions using Python code.  

Question-1

Using only one for loop and one print() function, display the following triangle.

Solution

for i in range(1,20,3):
  print(i*'*')

Question-2

Find the sum of the squares of the following numbers in two different ways: \(3, 7, 11, 15, 19, 23, \ldots, 107\).

• Use a for loop.

• Use a while loop.

Solution

total_for = 0   # for loop

for i in range(3,108,4):
    total_for += i**2

total_while = 0   # while loop
n= 3

while n < 108:
    total_while += n**2
    n += 4

print(f'for   loop answer: {total_for}')
print(f'while loop answer: {total_while}')

Sample Output
for loop answer: 107883
while loop answer: 107883

Question-3

Write a program that asks the user to enter integers until the sum of the given integers exceeds 100.

• Display the sum and count of the entered numbers.

• Use a while loop.

Solution

total = 0
count = 0

while total < 100:
    number = int(input('Enter an integer: '))
    total += number
    count += 1

print(f'Sum = {total}, Count = {count}')

Sample Output
Enter an integer: 3
Enter an integer: 90
Enter an integer: 6
Enter an integer: 10
<——————–>
Sum = 109, Count = 4

Question-4

Find the following product using a for loop and round the final answer to the nearest hundredth.

• \(\displaystyle \frac{10}{100}\frac{90}{99}\frac{89}{98}\frac{88}{97}\frac{87}{96}\frac{86}{95}\frac{85}{94}\frac{84}{93}\)

Solution

product = 10/100

for i in range(7):
    product *= (90-i)/(99-i)

print(f'Product: {round(product,2)}')

Question-5

Write a program that displays a rectangle using the characters * and ' ' (space).

• The rectangle has width many * characters on its upper and lower sides.

• The rectangle has length many * characters on its left and right sides.

• There is a ' ' space character between the * characters.

• use the following variables

  • width, height = 8, 5

Solution

width, height = 8, 5

for i in range(height):
    if (i!=0) and (i!=height-1):
        print('*'+(' '*(2*width-3)+'*'))
    else:
        print('* ' * width)

Question-6

Write a program that displays a wide, one-floor building using the characters * and ' ' (space).

• The building consists of room many rectangles, each with a size of width by height, stacked horizontally.

• Use the following variables

  • width, height, room = 4, 6, 10

• Some examples are as follows:

Solution

width, height, room = 4, 6, 10

for i in range(height):
    if (i != 0) and (i != height-1):
        print('*'+(' '*(2*width-3)+'*')*room)
    else:
        print('* ' * ((width-1) * room+1))

Question-7

Write a program that displays a tall building using the characters * and ' ' (space).

• The building consists of floor many rectangles, each with a size of width by height, stacked vertically.

• Use the following variables

  • width, height, floor = 5, 6, 2

• Some examples are as follows:

Solution

width, height, floor = 5, 6, 2

for i in range(floor*(height-1)+1):
    if i%(height-1) == 0:
        print('* ' * width)
    else:
        print('*' +' '*(2*width-3)+'*')

Question-8

Find the sum of the first \(1000\) terms of the following sequence:

\(\displaystyle \frac{1}{1\times 2}, \frac{1}{2\times 3}, \frac{1}{3\times 4}, \frac{1}{4\times 5}, ...\)

Solution

total = 0

for i in range(1, 1001):
  total += 1/(i*(i+1))
    
print(total)

Question-9

Write a program that prompts the user to enter any text, which may include characters such as digits and punctuations.

• Find the number of alphabet characters (a-z) in the given string.

• You can use the constant ascii_letters from the string module to access all lowercase and uppercase alphabet letters.

• Example:

  • Enter a string: Wer34

  • There are 3 alphabet letters in Wer34.

Solution

import string

text = input('Enter a text: ')
count = 0

for i in text:
  if i in string.ascii_letters:
    count += 1

print(f'There are {count} alphabet letters in {text}')

Sample Output
Enter a string: sD12&
There are 2 alphabet letters in sD12&

Question-10

Write a program that generates a random word with 5 characters using lowercase alphabet letters.

• You can use random.choice() to randomly choose a letter.

• The generated word does not have to be meaningful.

Solution

import string
import random

random_word = ''

for i in range(5):
    random_word += random.choice(string.ascii_lowercase)
           
print(f'Randomly generated word: {random_word}')

Sample Output:
Randomly generated word: iilor

Question-11

Write a program that prompts the user to enter an integer.

• Find the number of zeroes at the end of the given number.

• Use a while loop.

• Example:

  • Input: 1234500 —-> Output: 2

Solution-1

number = int(input('Enter an integer: '))
count = 0

n = number
while n%10 == 0:
  count += 1
  n /= 10

print(f'There are {count} zeroes at the end of {number}.')

Sample Output
Enter an integer: 278140000000000
There are 10 zeroes at the end of 278140000000000.

Solution-2

number = input('Enter an integer: ')
count = 0

i = -1
while number[i] == '0':
  count += 1
  i -= 1

print(f'There are {count} zeroes at the end of {number}.')

Sample Output
Enter an integer: 278140000000000
There are 10 zeroes at the end of 278140000000000.

Question-12

Write a program that selects a 3-digit random number (dividend) and a 1-digit random number (divisor).

• After 10 seconds, display the remainder and quotient.

• Use random.randint() to generate random integers.

Solution

import random
import time

divisor  = random.randint(1,9)
dividend = random.randint(100,999)
print(f'Divide {dividend} by {divisor}')

time.sleep(10)

print(f'Quotient  : {dividend//divisor}')
print(f'Remainder : {dividend%divisor}')

Sample Output
Divide 495 by 4
Quotient : 123
Remainder : 3