Largest of three numbers

Aim

Write a python program to find the largest of three numbers.

Algorithm

1. Start
2. Take input from the user for the first number
3. Take input from the user for the second number
4. Take input from the user for the third number
5. Compare the first number with the second number
   • If the first number is greater than the second number, go to step 6
   • else, go to step 7
6. Compare the first number with the third number
   • If the first number is greater than the third number, print the first number as the largest number
   • else, print the third number as the largest number
7. Compare the second number with the third number
   • If the second number is greater than the third number, print the second number as the largest number
   • else, print the third number as the largest number
8. End

Program

# Take input from the user
num1 = float(input("Enter the first number: \n"))
num2 = float(input("Enter the second number: \n"))
num3 = float(input("Enter the third number: \n"))
 
# Compare the first number with the second number
if num1 > num2:
    # Compare the first number with the third number
    if num1 > num3:
        print(f"{num1} is the largest number")
    else:
        print(f"{num3} is the largest number")
else:
    # Compare the second number with the third number
    if num2 > num3:
        print(f"{num2} is the largest number")
    else:
        print(f"{num3} is the largest number")
 

Sample Input/Output

Enter the first number:
10
Enter the second number:
20
Enter the third number:
30
30 is the largest number

Explanation

• The user is prompted to enter three numbers.
• The program compares the first number with the second number.
• If the first number is greater than the second number, the program compares the first number with the third number.
• If the first number is greater than the third number, the program prints the first number as the largest number.
• If the first number is not greater than the third number, the program prints the third number as the largest number.
• If the first number is not greater than the second number, the program compares the second number with the third number.
• If the second number is greater than the third number, the program prints the second number as the largest number.
• If the second number is not greater than the third number, the program prints the third number as the largest number.

Complexity Analysis

The time complexity for this program is O(1) as the program takes a constant amount of time to execute, irrespective of the input.

The space complexity for this program is also O(1) as the program uses a constant amount of space to store the input values and the variables.

How can you improve this program?

1. You can modify the program to take any number of inputs from the user and find the largest number among them.
2. You can modify the program to find the smallest number among the given numbers.
3. You can modify the program to find the second largest number among the given numbers.

Conclusion

In this tutorial, you learned how to write a Python program to find the largest of three numbers. You also learned about the algorithm, program, sample input/output, explanation, complexity analysis, and ways to improve the program. You can now practice writing similar programs to enhance your Python programming skills.