What is three address code?

Three address code is a type of intermediate code representation. It is a form of representing a computation that could be easily translated into machine language. The term "three address code" comes from the maximum number of addresses that are in the instructions.

Here are the steps to understand it:

1. Concept: In three address code, an instruction can have at most three addresses. For example, in a typical operation like A = B + C, there are three addresses involved, two for the operands (B and C) and one for the result (A).

2. Intermediate Representation: Three address code is often used as an intermediate representation of data in a compiler. After the source code is parsed, it is converted into an intermediate representation for further processing.

3. Types of Statements: There are different types of statements that can be represented in three address code, including assignment statements, unary operators, control flow, arrays, and function calls.

4. Advantages: The advantage of three address code is that it is easier to generate and optimize. It is a lower level representation of the code, closer to how the machine would execute it.

5. Example: Here is an example of three address code:

   t1 = B + C A = t1

   In this example, the operation B + C is performed first and the result is stored in a temporary variable t1. Then, the value of t1 is assigned to A. Each line of three address code performs a simple operation, which makes it easier to translate into machine language.