When writing computer programs, there are a variety of errors we can encounter.

Errors can exist within the program itself – called syntax errors or logic errors.

A syntax error is a mistake in the structure of the programming statements (the instructions written by the programmer do not meet the rules of the language). A logic error is when the program executes but produces a result that was not what the programmer intended.

Errors can also occur when the program is executed or run – these are known as run time errors.

To help reduce errors from data input, we use data validation techniques and error trapping methods.

An example of a validation error being returned