5.2. Language Translators

Question 1

Assembler

Answer 1

• Software that translates assembly language
  statements into machine code (binary) for execution
• The mnemonics used translates into machine
  opcodes
• Process simple because assembly language has a oneto-one relationship with machine code.

Question 2

Compiler

Answer 2

• Translates a high-level
  language program to
  machine code.
• Creates a .exe file which can
  be easily distributed.
• Once compiled, .exe file does
  not need to be compiled
  again, resulting in faster
  execution.
• Reports all errors at the end
  of compilation: difficult to
  locate errors∴ development
  process long.
• Only be produced when all
  errors are fixed.
• Used when development is
  completed.

Question 3

Interpreter

Answer 3

• Translates and executes a
  high-level language program,
  line-by-line.
• No .exe file created.
• Execution very slow –
  translated each time program
  run.
• Debugging easier/faster,
  since it stops translating
  when it reaches an error. This
  allows real time error
  correction.
• Can run program any time,
  even before code finished.
• Used during development

Question 4

Two-step translation

Answer 4

• Java and some other high level language programs
  may require two-step translation, i.e., they will be partially compiled and partially interpreted
• Java code first translated to bytecode by Java compiler
• Bytecode finally interpreted by the Java Virtual
  Machine to produce machine code

Question 5

Integrated Development Environment (IDE) features

Answer 5

Coding, Initial Error Detection, Presentation, Debugging

Question 6

Coding

Answer 6

• Context-sensitive prompts: Displays choice of
  keywords and available identifiers appropriate at
  current insertion point and provides choices in
  alphabetical order
• Highlights undeclared/unassigned variable
  identifiers

Question 7

Initial Error Detection

Answer 7

• Dynamic syntax checks: Automatic checking and
  highlighting of syntax errors, as soon as line typed
• Type checking & parameter checking

Question 8

Presentation

Answer 8

• Prettyprint: Automatic indentation and colorcoding of keywords
• Expand and Collapse code blocks: Saves excessive
  scrolling if collapsed, and easy to see global
  variable declarations and main program body
  when collapsed

Question 9

Debugging

Answer 9

• Single stepping: Executes program line-by-line to
  see the effect of each statement on variables
• Breakpoints: Pauses program at a specific line to
  ensure program operates correctly up to that line
• Variables/expressions Report Window: Monitors
  variables for comparing values.