Blockchain Developer Certification Practice

What type of variable is stored in the EVM Stack?

1. Function arguments

2. State variables

3. Local variables of non-reference types

4. Perpetual state data

The correct answer is: Local variables of non-reference types

The Ethereum Virtual Machine (EVM) Stack is designed to hold local variables and temporary data needed during contract execution. Local variables, particularly of non-reference types, are used for intermediate computations, function parameters, and for keeping track of state within the scope of a function. These variables are placed on the stack for efficient access and manipulation as they have a limited lifetime and relevance during the execution of a specific function call. Local variables of non-reference types include primitive data structures such as integers or booleans, which are directly stored in the stack. This contrasts with state variables and other data types which have a longer lifespan and are stored in storage or memory. The stack operates on a last-in-first-out (LIFO) basis, which is ideal for handling these temporary values that don't require persistent storage beyond the current function's execution.