20.py

#example 1

friends = []
for i in range(3):
    name = input(f"Enter friend {i+1} name: ")
    friends.append(name)
with open("friends.txt", "w") as file:
    for friend in friends:
        file.write(friend + "\n")

print("Friends saved to friends.txt")

#example 2

name = input("Enter student name: ")
marks = input("Enter marks: ")
with open("marks.txt", "a") as file:
    file.write(f"{name} - {marks}\n")

print("Data appended to marks.txt")



#example 3

filename = input("Enter file name: ")
with open(filename, "r") as file:
    lines = file.readlines()
    count = len(lines)

print(f"Total number of lines: {count}")

#example 4

# Ask user for name to search
search_name = input("Enter name to search: ")

found = False

with open("friends.txt", "r") as file:
    for line in file:
        if search_name.lower() == line.strip().lower():
            found = True
            break

if found:
    print("Found!")
else:
    print("Not Found!")