Compilation, Interpretation & Subroutines Flashcards
What is the main difference between compilation and interpretation?
Compilation changes high-level code into machine code before running it. Interpretation runs code line by line without changing it into machine code.
What are the levels of programming languages?
High-Level Languages (e.g., Java, C++)
Low-Level Languages (e.g., Machine Code)
Assembly Language (between high and low level)
What are the main steps in the compilation process?
Lexical Analysis
Syntax Analysis
Semantic Analysis
Optimization
Code Generation
Linking
What are the advantages of compilation?
Faster execution after compilation.
Improved machine code.
Optimized for specific platforms.
What are the disadvantages of compilation?
Longer compilation time.
Depends on hardware (code needs recompilation for different platforms).
What is cross compilation?
Compiling code on one platform to run on another.
What is an interpreter?
A program that reads and runs code line by line.
What are the advantages of using an interpreter?
Easier debugging and testing.
Works on any platform.
Runs and modifies in real-time.
What are the disadvantages of using an interpreter?
Slower execution than compiled code.
Line-by-line interpretation adds extra overhead.
How does combined compilation and interpretation work?
High-level code is compiled into an intermediate form (like bytecode), which is then interpreted or JIT compiled.
What is a Virtual Machine (VM)?
A software that acts like a physical computer to run intermediate code.
What is the most common virtual machine in programming?
The Java Virtual Machine (JVM), which executes Java bytecode.
What is JIT compilation?
A technique where bytecode is compiled to machine code just before execution to improve performance.
What are subroutines?
Reusable code blocks that perform a task and can be used anywhere in a program.
What are the advantages of using subroutines?
Reuse code
Keep it organized
Reduce repetition
What is a stack used for in subroutine management?
To store return addresses, parameters, and local variables.
What are the primary operations performed on a stack?
Push (add to top) and Pop (remove from top).
What are the call and return instructions used for?
Call stores the return address and jumps to the subroutine, while ret retrieves the return address from the stack.
What is Reverse Polish Notation?
A way of writing math where operators come after numbers (e.g., 3 4 + instead of 3 + 4).
Why is Reverse Polish Notation useful?
No need for parentheses, making stack calculations easier.
How would you express 3 + 4 * 2 in RPN?
3 4 2 * +
What is an operand stack?
A data structure that stores numbers and results while calculating.
What are stack machines?
Computers that use stacks instead of registers to perform operations.
What is the difference between unconditional and conditional jumps?
Unconditional Jump: Always transfers control to a specific address.
Conditional Jump: Transfers control based on a condition (e.g., if x == 0).
What is the Shunting-Yard Algorithm used for?
Converting infix expressions (e.g., 3 + 4 * 2) to postfix (RPN) expressions.
What type of architecture does JVM follow?
An architecture that uses a stack for pushing and popping values during operations.
Why is Java considered portable?
Java code turns into bytecode, so it can run on any computer with a JVM.
What is a stack frame?
A stack contains local variables, parameters, and return addresses used during subroutine calls.
Why do subroutines save registers?
Saves the caller’s register values during execution.
Why are stacks efficient for temporary storage?
They follow the LIFO (Last In, First Out) principle, making push and pop operations fast.
