(ROBOGUIDE) Fanuc Karel Stack Overflow error

Question

When running a karel program in roboguide a stack overflow error occurs, even though there is no recursion. There is no other information given by roboguide.

Answer 1

Check the "Stack Usage" section of your Karel manual

When a program is executed, a stack of 300 words is allocated unless you specify a stack size. The stack is allocated from available user RAM. Stack usage can be calculated as follows: • Each call (or function reference) uses at least five words of stack. • In addition, for each parameter and local variable in the routine, additional space on the stack is used, depending on the variable or parameter type as shown in

First try increasing the stack size of your program (add under the PROGRAM keyword)

%STACKSIZE = 4000

Second, as the manual states the stack size include all parameters (there is a table in the manual that specifies the size of each data type). In my case, the culprit was my generous usage of string variable declaration

VAR
   msg:STRING[200]
   even_worse:ARRAY[10] OF STRING[200]

The string parameters can quickly add up, especially arrays of strings. Make sure you only declare what you need, or even better don't use the local variable if not strictly needed. In Fanuc's Karel the stack space is tight, make everything count.