2. Errors in logic
Look at the following sentence:
My pencil just rode a bike to London
While it is a grammatical sentence, it makes no sense. Pencils don't ride bikes. Somewhere, the programmer writing this sentence has made a logical error. Only the programmer can spot these logic errors because the computer will just do exactly as it has been told.
Here are some very common logic errors.
Infinite loops
This pseudocode has a logic error
Line 30: mynumber = 1
Line 31: WHILE mynumber != 2
Line 32: PRINT mynumber
Line 33: END WHILE
The mynumber variable is set to 1 in line 30, and nothing ever changes it - so the code loops around forever. The code below guarantees the while loop can end because of the increment mynumber command at line 33
Line 30: mynumber = 1
Line 31: WHILE mynumber != 2
Line 32: PRINT mynumber
Line 33: INCREMENT mynumber
Line 33: END WHILE
Challenge see if you can find out one extra fact on this topic that we haven't already told you
Click on this link: What are some examples of logic errors in programming?