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1. Print "Hello, World!"2. Add Two Numbers3. Swap Two Variables4. Find ASCII Value of a Character5. Check Even or Odd6. Find Largest of Two Numbers7. Find Largest of Three Numbers8. Check Positive, Negative, or Zero9. Convert Kilometers to Miles10. Convert Celsius to Fahrenheit11. Calculate Area of a Triangle12. Calculate Simple Interest13. Calculate Compound Interest14. Calculate Square Root15. Convert Seconds to Hours, Minutes, and Seconds16. Calculate Body Mass Index (BMI)17. Check Leap Year18. Find Absolute Value19. Calculate Age from Birth Year20. Sum of First N Natural Numbers21. Calculate Power Without Using pow()22. Print Multiplication Table23. Convert Decimal to Binary24. Convert Binary to Decimal25. Calculate Electricity Bill

Check Positive, Negative, or Zero in Python

Zero is not positive. Put it in its own branch or you will lie to the user.

BeginnerBasic Python ProgramsExample 8 of 25
check-positive-negative-or-zero.py
1# Program to check if a number is positive, negative, or zero
2

3num = float(input("Enter a number: "))
4

5if num > 0:
6    print(num, "is positive")
7elif num < 0:
8    print(num, "is negative")
9else:
10    print("The number is zero")

Output

Enter a number: -3
-3.0 is negative

In this one

  • zero needs its own branch
  • > 0 is not "not negative"

What's going on

Three buckets: > 0, < 0, else. Zero has to be the else. Stick it under > 0 and you print "0.0 is positive". I've marked that wrong on quizzes.

float so -0 still comes through as 0.0. Fine.

After this program

If the idea is still fuzzy, read Day 1: Introduction to Python in the Python course. For a short check, try the Python quiz (300 questions). Stay with all 25 basic python programs, or see every topic on Python exercises.

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