Errors
Syntax errors
When the programmer fails to obey one of the grammar rules of the programming language
Difficult to find
Usually down to wrong case, wrong punctuation or lack of punctuation
Most common are:
Quotes around a string
A colon at the end of an iteration or selection
Name errors
Misspelt a variable or a function
Forgotten to import a module
Forgotten to define a variable
Logic errors
Most difficult to find
Usually no obvious indication of the error within the software
The code will run successfully but it won't do what you intend it to do - produce incorrect results
Common reasons are:
Programmer didn't understand how the program was supposed to work
Careless programming
The programmer didn't understand the individual operation of each part of the program and how it helped the program to work
Runtime errors
Error that doesn't appear until the program is run as it is intended
eg. when the program runs out of memory, or when the code isn't compatible with the browser or program