Question

Which of the following intermediate code representations is typically used to represent expressions where each instruction has at most three operands?

• A. Postfix Notation
• B. Syntax Trees
• C. Three Address Code
• D. Directed Acyclic Graph

Hint:

Three Address Code is highly beneficial for code optimization because its simplified, linear format makes it easy to apply techniques like constant folding or common subexpression elimination.

Answer 1

The Correct Option is C

Concept: Intermediate code acts as a bridge between the high-level source code and the machine-specific assembly code.
• Linear Representation: Represents the program as a sequence of simple operations.
• Quadruples/Triples: Common implementations of three-address code.

Step 1: Understanding the structure of instructions.
Three-address code (TAC) consists of instructions with at most three addresses. A general instruction looks like: $x = y \text{ op } z$

Step 2: Counting the operands.
In the format $x = y \text{ op } z$: $x$ is the result address (1st), $y$ is the first operand (2nd), and $z$ is the second (3rd). Complex expressions are broken down into multiple TAC instructions.

Step 3: Comparing with other types.
Postfix (A) is a 1-address/stack-based representation. Syntax Trees (B) and DAGs (D) are graphical, not instruction-based representations.