When working with numbers in JSP/Java, it is often necessary to extract specific parts of a double, such as the whole number or the fractional part. In this article, we will explore different methods for extracting these parts and how they can be implemented in your code.

First, let's define what a double is. A double is a data type in Java that is used to store decimal values. Unlike integers, which can only store whole numbers, doubles can hold both whole and fractional numbers. This makes them useful for calculations and other tasks that require more precision.

To extract the whole part of a double in JSP/Java, we can use the Math.floor() method. This method takes a double as an argument and returns the largest integer less than or equal to the given number. For example, if we have a double with the value of 3.75, using Math.floor() will return 3. This is because 3 is the largest integer that is less than or equal to 3.75. Let's see an example of how this can be used in JSP/Java:

## <%

## double number = 3.75;

## int wholePart = (int) Math.floor(number);

out.println("The whole part of the number is: " + wholePart);

## %>

In the above code, we first declare a double variable called "number" with the value of 3.75. Then, we use the Math.floor() method to extract the whole part of the number and store it in an integer variable called "wholePart". Finally, we use the out.println() method to print the result to the screen.

Now, let's move on to extracting the fractional part of a double. To do this, we can use the % (modulus) operator. This operator returns the remainder of a division operation. For example, if we have a double with the value of 3.75, using the % operator with a divisor of 1 will return 0.75, which is the fractional part of the number. Here's an example of how this can be implemented in JSP/Java:

## <%

## double number = 3.75;

## double fractionalPart = number % 1;

out.println("The fractional part of the number is: " + fractionalPart);

## %>

In the above code, we first declare a double variable called "number" with the value of 3.75. Then, we use the % operator with a divisor of 1 to extract the fractional part of the number and store it in another double variable called "fractionalPart". Finally, we print the result to the screen using the out.println() method.

It is worth noting that when using the % operator, the result will always be a double. If you want to store the fractional part as an integer, you can use the type casting method we used in the first example.

In addition to the methods mentioned above, there are other ways to extract the whole and fractional parts of a double in JSP/Java. For example, you can use the String.split() method to split the number into two parts at the decimal point, then convert each part into the desired data type. You can also use the String.format() method to format the number as a string and then extract the parts using string manipulation techniques.

In conclusion, extracting the whole and fractional parts of a double in JSP/Java can be done using various methods.