Unit-4

18) # Define the input and output file names 
import os
input_file_name = 'source.txt'
output_file_name = 'sorted_words.txt'
if not os.path.exists(input_file_name):
    print(f"Error: Input file '{input_file_name}' not found.")
else:
    with open(input_file_name, 'r') as infile:
        sorted_words = sorted(infile.read().splitlines(), key=str.lower)      
    with open(output_file_name, 'w') as outfile:
        outfile.write('\n'.join(sorted_words))
    print(f"Sorted words have been written to '{output_file_name}'.")


19) 
def print_lines_in_reverse(filename):
    try:
        with open(filename, 'r') as file:
            for line in file:
                print(line.strip()[::-1])
    except FileNotFoundError:
        print(f"File '{filename}' not found.")
filename = 'example.txt'
print_lines_in_reverse(filename)


20)
with open("f:\\mytxt.txt","r") as file: 
     f=file.read() 
     chr_cnt=len(f) 
     word_cnt=len(f.split()) 
     line_cnt=f.count('\n')+1 
print("No. of Characters:",chr_cnt) 
print("No. of Words:",word_cnt) 
print("No. of Lines:",line_cnt)


21)
import array 
arr=array.array('i',[1,2,3,4,5])  
print(arr) 
arr.append(32) 
print(arr) 
arr.insert(3,32) 
print(arr) 
arr.reverse() 
print(arr)


22)
#Adding two Matrix
a = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
b = [[1, 1, 1], [1, 1, 1], [1, 1, 1]]
c = [[a[i][j] + b[i][j] for j in range(len(a[0]))] for i in range(len(a))]
for i in c:
    print(i)

#Transpose Matrix
print("Before Transpose") 
for i in a: 
     print(i) 
for i in range(len(a)): 
    for j in range(len(a[0])): 
        c[i][j]=a[j][i] 
for i in c: 
    print(i)

## Multiplication for two matrix 
for i in range(len(a)): 
    for j in range(len(a[0])): 
        c[i][j]=0 
        for k in range(len(a)): 
            c[i][j]+=a[i][k]*b[k][j] 
print("Multiplication of two matrix") 
for i in c: 
    print(i)


23)
#create a class that represents a shape
import math
class Shape:
    def area(self): pass
    def perimeter(self): pass
class Circle(Shape):
    def __init__(self, radius): self.radius = radius
    def area(self): return math.pi * self.radius ** 2
    def perimeter(self): return 2 * math.pi * self.radius
class Triangle(Shape):
    def __init__(self, base, height, *sides):
        self.base, self.height, self.sides = base, height, sides
    def area(self): return 0.5 * self.base * self.height
    def perimeter(self): return sum(self.sides)
class Square(Shape):
    def __init__(self, length): self.length = length
    def area(self): return self.length ** 2
    def perimeter(self): return 4 * self.length
shapes = [
    Circle(4),
    Triangle(3, 4, 3, 4, 5),
    Square(3)
]
for shape in shapes:
    print(f"{shape.__class__.__name__} - Area: {shape.area()}, Perimeter: {shape.perimeter()}")