There are four stages in the compilation of a program written in a high-level language.
a) Four statements and four compilation stages are shown below. Copy the diagram below and connect each statement to the correct compilation stage.

b) Write the Reverse Polish Notation (RPN) for the following expression.

c) An interpreter is executing a program.
The program uses the variables a, b, c and d.
The program contains an expression written in infix form. The interpreter converts the infix expression to RPN. The RPN expression is:

The interpreter evaluates this RPN expression using a stack.
The current values of the variables are:

i) Copy the diagram below and show the changing contents of the stack as the interpreter evaluates the expression. The first entry on the stack has been done for you.

ii) Convert back to its original infix form, the RPN expression: 

iii) One advantage of using RPN is that the evaluation of an expression does not require rules of precedence.
Explain this statement.

Transcribed Image Text:

Statement Compilation stage This stage can improve the time taken to executex y + 0 Lexical analysis This stage produces object code Syntax analysis This stage makes use of tree data structures Code generation This stage enters symbols in the symbol table Optimisation