Jul 162009
 

I kept finding more and more bugs with 1.2.  The ± thing, a problem with equals followed by a parenthetical, echoing variables without arithmetic.

I believe all the bugs I currently know about are fixed. Plus, I fixed some performance issues in how fast an equation is solved (barely noticeable on most equations though).  And I fixed the problem with the horizontal division bar and the bar over a rooted expression where they would disappear during a selection animation.

Features added:

You can now copy an equation out of the calculator as an image and paste it anywhere that is accepting of images, such as email.  Click and hold on the equation for half of a second and the copy bubble will appear when you let go.

The ± button works in front of numbers, variables, constants and it also will swap the sign of these types.  Also in front of parentheses, and functions to negate the calculated value. Pressing the ± button after the close parenthesis of a parenthetical or a function will swap the sign of the whole expression.

Read This for more features added since 1.1.

 Posted by at 10:43 am
Jul 132009
 

Pressing the ± button doesn’t behave completely like it should. Pressing 6, ±, +, 8 will result in 2 because the ± changes the sign of the 6. Pressing ±, 6, +, 8 also equals 2 because the 6 become negative from the ±, this is also correct. However, say x is set equal to 6, pressing x, ±, + 8 will equal 2 correctly. Pressing ±, x, + 8 will equal 8. This is because the ± starts input for a negative number then pressing a variable following it yields an implicit multiplication, much like 2x, with is interpreted as 0•x which equals 0.  Plus 8 will then equal 8.

This is part of a much bigger problem with the ± key. ±, log(1000) yeilds -•log(1000) which is also 0 not 3.  This is now my number one priority.

For now, just remember, ± changes the sign of the number or variable typed.  It is not the negative operator as it sometimes acts. But it will be…

 Posted by at 8:42 pm
Jul 122009
 

sCalc 1.1 has been on the app store for a very long time with the note, “saving history coming soon.” Over the past few weekends I’ve finally implemented history saving.

The quadratic equation

The quadratic equation

  • Swiping on the equations allow you to delete old equations that you no longer need.
  • The variable list has been moved into the “Variables” button the top bar.  You can swipe to clear these as well.
  • The catalog displays all the functions the calculator can perform.  This is not useful at all right now as there is a key for all operations in the catalog.  But it’s a foundation for further work.

I also added a ‘2nd’ button that swaps keys like your expect.  Very few change though, again it is foundational.  The keys that do change are ‘x’ => ‘y’; ln => lg; ‘=’ => ‘Ans’.

Further changes include updates to pretty printing the equations.  Division of two simple elements (numbers or variables) are displayed as 1/2 instead of 1 over 2.  Also, 2•x is now displayed with the implicit multiplication as 2x.

So, most changes where made with the future in mind and to fix the problem with losing the history when the application starts. I’ve been using the saved history for about a week so I feel it is necessary to get that feature out before adding more.

I’ll post more about future features soon.

 Posted by at 12:40 pm
Jul 122009
 

I’ve decided to start posting articles and general information about the changes made to and issues found in my iPhone apps.  The main reason for starting this is the release of sCalc 1.2 which is in app store review right now.  The next post will be all about it.

 Posted by at 10:59 am