Instant Calculator

Instant Calculators allow web-based users to make quick numerical calculations, including the creation of graphs and tables through any web enable application (including emails, websites, desktop gadgets and mobile phones). All the calculators seen on CodeCogs can be embedded onto another website using a short script. This makes them ultra flexible and very portable.

Key features

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Instant Calculators, provide a simple and clean interface to a numerical calculation, allowing users to instantly make calculations without having to download or install any software. They can be embedded into any system that accepts HTML and can connect to the world wide web.

The code behind the calculators in all written in C or C++ and resides on CodeCogs. The enables complex calculations to be performed at speeds not possible through a standard website languages. The source code is not shared (unless you otherwise licence it) and it is impossible for the user to access it - so you retain complete control over your interlectual knowledge, design and idea.

Creating a new Calculator

You can create a new Instant Calculator any time, by merely submiting a function to CodeCogs at: http://www.codecogs.com/submit.php?mode=NEW

Once you have submited and confirmed the function, it will pass through our QA system and on acceptance will be compiled for use as an Instant Calculator. This process usually takes 1 working day.

Once active you can start using and sharing it.

Remember: If you wish to keep the content of your function private, you should select 'Private' under Licence Type.

Integration

To integrate an Instant Calculators into a website follow these steps:

• Find the module that interest you.
• Look for the Instant Calculators - this is usually on the right side of the screen along side the main function declaration.
• Click on the text just below the Calculator, which says "Add calculator to your site or email"
• This will open up a hidden section and display three alternative ways for you to share the calculator.
• Copy the code within the section called "Embed onto your website with:" and paste this directly into the body section of the website. Save the page to the live server and the calculator will immediately be visible.
• If you are using a forum or blog, you may need to goto 'Edit HTML' (or equivalent) and submit the code within this view. Some forums allow HTML to be entered with the main text. [We will shortly be releasing a script to automate this for other forums systems]

Other benefits

Any component that is available as an instant calculator can also (at your discresion) be downloaded as an Excel add-in and used seemlessly from within Microsoft Excel (tested on Excel 2000 to 2003).

Example 1

To illustrate how easy this is, consider this: You want to solve this well know dynamics equation in mechanics: . Returning the final velocity (v) for a given initial velocity (u) and acceleration (a) over the distance (s). First we need a slight rearrangement of the equation, i.e.:

Now we can write our code, but with these point in mind (n.b. colors of points are matched to code):

• We're doing some slightly complex maths, due to the square root (sqrt in C), so we'll include the C maths library (i.e. #include <math.h>).
• All our variable are real numbers, so for maximum precision we'll use the C data type called 'double'.
• And our function also returns a real number, so the type before the function name will also be 'double'.

#include<math.h>

double velocity(double u, double a, double s)
{
  return sqrt(u*u + 2*a*s);
}

If you now goto the Submission system and submit the above code, you'll see you first calculator generated. Remember it won't work immediately, it'll have to pass through our QA process first [Incidentally we're working to streamline this so calculators can go live immediately - but thats a few months off]

Example 2

The previous example was very mathematic, but lets say you want a calculator that counts the number of letters in a sentence, how would this be done. There aren't any prebuilt routines in the C function library that achieve this so we'll have to write this all ourselves. Points to consider:

• A word must have letters a to z, in either upper or lower case. If you look at an appropriate ASCII table, you see that:
  • A to Z are represented in a computer with numbers 65 to 90
  • a to z are represented with numbers 97 to 122
• We don't need any other C function libraries, so we won't be using #include
• We'll accept a pointer to character string, which is written as 'char*'. This will be terminated by a zero (0) - a standard thing in C.
• And we'll return the number of letter using an integer, which is C is represented by 'int'

So now to the code (again note the colors that try to link the code to the above bullet points):

int lettercount(char* string)
{
  int count=0;
  int i=0;
  while(string[i]!=0)
  {
    if((string[i]>=65 && string[i]<=90) || (string[i]>=97 && string[i]<=122)) count++;
    i++;
  }
  return count;
}

Again goto the Submission system and see what happens.

As a general concluding comment. The submission system will try to create as much documentation as possible. But it can't possible know what you are ultimately trying to do. Therefore to make the instant calculator you create more user friendly, make sure you document at the very least each of the input parameters. You'll be asked for this information once you submit and move to the second page.