Javascript Program to Check if a number is Positive, Negative, or Zero

You will be using the if...else if...else statement to write the program.

Example 1: Check Number Type with if...else if...else

// program that checks if the number is positive, negative or zero
// input from the user
const number = parseInt(prompt("Enter a number: "));

// check if number is greater than 0
if (number > 0) {
    console.log("The number is positive");
}

// check if number is 0
else if (number == 0) {
  console.log("The number is zero");
}

// if number is less than 0
else {
     console.log("The number is negative");
}

Output

Enter a number: 0
The number is zero.

The above program checks if the number entered by the user is positive, negative or zero.

• The condition number > 0 checks if the number is positive.
• The condition number == 0 checks if the number is zero.
• The condition number < 0 checks if the number is negative.

The above program can also be written using the nested if...else statement.

Example 2: Check Number Type with nested if...else

// check if the number is positive, negative or zero
const number = prompt("Enter a number: ");

if (number >= 0) {
    if (number == 0) {
        console.log("The number is zero");
    } else {
        console.log("The number is positive");
    }
} else {
    console.log("The number is negative");
}

Output

Enter a number: 0
You entered number zero

The above program works the same as Example 1. However, the second example uses the nested if...else statement.