concatinated zeros don't display

[+BoxmanCrew]

I've built a cartridge that collects user inputs, does a "numeric operation" to calculates a new value for the variable. I later concatenate those variables together to produce the geocache coordinates. When the new value has a leading zero it does not display in the concatenated value. Example N42 12.012 Will display as N42 12.12. What is the best way to make sure zero values are displayed?

 

A second issue I found was that if the user enters a 1 (for example) and I subtract 2 the resulting negative number will crash the cartridge when the concatenation is done. Is there a way to mistake proof this?

 

I am using Urwigo as my editor.

Edited July 2, 2017 by BoxmanCrew

[+BoxmanCrew]

OK. I found my own solution to the zero's being dropped. I did the concatenation into a new variable and set the type to string instead of number.

 

Still looking for suggestions on error proofing so I don't end up with a negative number if the user enters an incorrect value. Is there a way to set the resulting value to an absolute value? For now I changed the input to choice and limited the values available to prevent numbers that would not work properly.

Edited July 2, 2017 by BoxmanCrew

[+charlenni]

For the first problem, you could use the Lua function "tostring()" to convert a number into a string.

 

For the second, you could check the entered number in the input event. Check, if the number is lower than 0 or greater than 9. If so, display a message, that the number is wrong. If you don't want to give a hint, you could use the Lua function "math.abs()" (see http://lua-users.org/wiki/MathLibraryTutorial) to get the absolut value.