How to Check if a Number Is Positive or Negative in Java

Check if a Number is Positive or Negative in Java

When learning the Java programming language, it's important to understand how to determine whether a number is positive or negative. Knowing when to use a positive or negative integer can be useful when writing algorithms or creating mathematical equations.

In this tutorial, we'll discuss how to check if a number is positive or negative in Java. We'll also look at some examples to help you better understand this concept.

Checking if a Number is Positive or Negative with an If Statement

The simplest way to check if a number is positive or negative is to use an if statement. For example, consider the following code:

int myNum = 10;
if (myNum > 0) {
    System.out.println("The number is positive.");
} else {
    System.out.println("The number is negative.");
}

In this example, we check if the value of the myNum variable is greater than 0. If it is, we print out a message saying that the number is positive. Otherwise, we print out a message saying that the number is negative.

Using Math.signum()

Another way to check if a number is positive or negative is by using the Math.signum() method. This method takes one argument, which is a real number, and returns 1 if the number is positive, 0 if the number is 0, and -1 if the number is negative.

For example, consider the following code:

double myNum = -10.5;
// Using Math.signum() to check the sign of a number
int result = Math.signum(myNum);
if (result == 1) {
    System.out.println("The number is positive.");
} else if (result == 0) {
    System.out.println("The number is zero.");
} else {
    System.out.println("The number is negative.");
}

In this example, we use the Math.signum() method to check the sign of the myNum variable. If it returns 1, we print out a message saying that the number is positive. If it returns 0, we print out a message saying that the number is zero. Otherwise, we print out a message saying that the number is negative.

Conclusion

In this tutorial, we discussed how to check if a number is positive or negative in Java. We looked at two different approaches for doing this: using an if statement and using the Math.signum() method.

Now you have the knowledge you need to check if a number is positive or negative in your own Java programs!