Python program checks if the number is positive, negative, or 0

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In this example, you will learn to check if the user input number is positive, negative, or zero. The if...elif...else and nested if...else statements can solve this problem.

To understand this example, you should understand the followingPython programmingTopic:

• Python if ... else statement

• Python input, output and import

Source code: Using if ... elif ... else

num　=　float(input("Enter a number:　"))
if　num　>　0:
　　　print("Positive number")
elif　num　==　0:
　　　print("0")
else:
　　　print("Negative number")

Here, we use the if...elif...else statement. We can use nested if statements to perform the following operations.

Source code: Using nested if

num　=　float(input("Enter a number:　"))
if　num　>=　0:
　　　if　num　==　0:
　　　　　　　print("0")
　　　else:
　　　　　　　print("Positive number")
else:
　　　print("Negative number")

The outputs of the two programs are the same.

Output1

Enter a number:　2
Positive number

Output2

Enter a number:　0
0

If the number is greater than zero, it is a positive number. We check this in the if expression. If it is False, the number will be zero or negative. This is also tested in subsequent expressions.

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