GATE CS 1995 Q1.11 — Lexical Analysis

In a macro definition, the placeholders specified in the header are called formal parameters (or dummy arguments).

In the given macro definition:

macro Add x, y
      Load y
      Mul x
      Store y
end macro

Here, $x$ and $y$ are placeholders that will be replaced by real arguments during macro expansion. Therefore, they are formal parameters.

When the macro is invoked (for example, Add A, B), the arguments $A$ and $B$ provided at the call site are known as the actual parameters.