Logic and Program

Logic and Program

1. Translator

   • Compiler
     • The code written by the programmer is called the source code
     • The code produced by the compiler is called the object code
   • Interpreter
     • no object code is produced
     • translate each line of code and executes it immediately
     • it reaches a line with a syntax error. it stops and displays an error message

2. Validation

   • Range check
     • A number or date is within a sensible/allowed range
   • Type Check
     • Data is of the right type, such as integer, letter or text
   • Length check
     • Text entered is not too long or too short - for example a password is between 8 and 15 characters
   • Presence check
     • Checks that data has been entered, i.e. the field has not been left blank
   • Format check
     • Checks that the format of, for example a postcode or email address is correct

3. Truth table

   • Purpose
     • Show all output from all possible combinations of inputs from a Boolean expression