User:Filipporussia165sd561ds15
I recently made my own calculator and I was surprised how difficult it was. Yes of course a simple calculator that supports the basics is not very hard to do. But I had the following specification:
Use PHP, HTML, CSS and javascript only One input field Result history No refreshing the page Support trigonometric functions Support for Pi, Sqrt and logarithm
The real challenge is the "one input field"-thing. If you let the user write numbers and operators in the same input field you will have to separate them from each other later to perform the calculations. That is much easier said that done. For example, how do you determine the different meanings of the substring "-3" in "sqrt(6-3+5)" and "sqrt(-3+5)"? The answer is regular expressions.
When you develop your pregnancy calculator you have to use a lot of regex to separate numbers, operators and functions form each other. Take this string for example: "3+4.2-1". You have to break it into 3 parts and you have to know which pars that is operators and which parts that is numbers. When this is done you just have to evaluate the expressions in the correct mathematical order, put the results together and evaluate the parts again until there is just one part left and (hopefully) there is your answer. The advanced calculator stuff like Pi, square root, trigonometric function etc is solved with built in PHP functions.
To solve the "no refreshing the page" you have to use Ajax. Ajax is a quite popular method to add content to a page that is already loaded. I would recommend you to use the javascript library jQuery to send ajax-requests and to handle the response. The response data should be written on the page in a way that you can see result history. Thanks to jQuery there is only need for a couple of hundreds line of javascript and the code is not messy at all. jQuery can do a lot more than sending HTTP-requests. You can animate DOM elements, add event listeners, manipulate with CSS etc.
When you are writing a program or anything that will be used by others than yourself you have to write test code. A lot of test code. You will need approximately 50+ different expressions to test if your calculator calculates them correctly. You will probably fail a lot of times before you pass them all. Increased fuel prices are the talk of the town. It has not only had an impact on the car running costs but has also hugely affected the pockets of car owners. In addition there are new car tax rates implemented by the UK government. As per the new law the running costs will vary from car to car depending upon various factors that include the number of miles you drive, your insurance policy, how reliable your car is etc. Unfortunately this is also one of the taxes that we all have to pay for, and its about 100 pounds a year for a reasonably non polluting car, the car tax increases slightly for the large, gas guzzling cars. With these two factors in place that driving your dream car is definitely going to be a little more expensive now.
The new car tax prices have made car owners cautious of using their cars as now they need to pay taxes according to the tax band their car fits into. One of the best ways to find out the amount that you need to pay is by calculating car tax prices as per the new tax bands. Though it is a difficult task to calculate tax prices keeping all the variants in mind but at the same time you should have a reliable method to do these calculations yourself.
One of the finest ways to calculate the running cost of your car is by making use of car tax scientific calculator. You can either make use of these calculators online or can buy one for your personal use. There are many online sources that offer you free online car tax calculator services. In order to make appropriate use of these calculators all you need to do is just enter the information into the calculator to compute your monthly car payments. These calculators make use of different variables to help you calculate the right amount. Online car tax calculators are embedded with all the rates and information as per the latest norms and offer you tax rates as per the inputs that you make. This is one of the simplest ways to calculate your car tax rates.
These currency converter are comprehensive, user-friendly, and reliable as they do all the necessary calculations for you. These mortgage calculator are designed to make life easier for you. By calculating the amount in advance that you need to pay in term of car taxes, you can easily plan your expenses and live a stress free life.
There is nothing better than a multi-utility resource in life which solves most of our problems. On such device or rather resource online is a scientific and numeral system BMI calculator with credit and currency calculator. With such a resource you are never at loss because no matter what problem, you have, it can be solved. Here are the benefits:
1. Universal, ready presence: When you have such a ovulation calculator online, you know that you are just a mouse click away from the problem that you are facing.
2. Time saving; You are saving on time because you just have to go to the website that has a multipurpose percentage calculator, bookmark it and you can definitely solve your problems easily.
3. Money saving: You can imagine the cost of a calculator that is packed with functionalities to calculate basic mathematical problems, scientific problems, currency conversion and credit management. But you can get all of this free online, isn't it amazing?
4. All- in- one functionality: You can use the scientific calculator to solve complex scientific and mathematical problems. The numeralconversion calculator can be used to deduce different numeral systems. The credit calculator can help you manage your household and business budget while the currency converter is self explanatory as helping you find the value of transactions or money in the other country's currency.
5. User friendly: Now you can make use of such calculator online without any qualms, the instructions on how to go about using them are mentioned. Most of them are user-friendly, for the others that you may not comprehend at first sight, you can always read the instructions and do them with remarkable ease.
Thus we see that there are manifold benefits to an online calculator that packs in a lot of these features. With the versatile nature of this powerful handy tool, you will never been at loss in your professional or personal life.