Compilers are programs that convert a code written in a high-level programming language such as C++ or Java into machine code that can be run on the computer. A compiler is an essential tool for every software developer. It takes the source code, which can be much more complex and difficult to read than machine code, and converts it into easy-to-understand and easy-to-execute machine code. Despite being incredibly important and efficient, compilers can only interpret a certain range of language features, so it is important for developers to know what is and isn't considered when the compiler is creating the machine code.
In this guide we will provide a comprehensive overview of what is and is not considered by compilers, with a focus on the most popular programming languages - C++ and Java. We will also discuss some common errors that developers might encounter when using a compiler and provide recommendations on how to avoid them.
Types of Statements Considered by Compilers
The two primary types of statements that compilers do consider are: external declarations and internal declarations.
External Declarations
External declarations are the actual declarations written by a programmer in a coding text editor or software development environment. These are then compiled into machine code and delivered to the user. Examples of external declarations include function names, variables, classes, and interfaces.
Internal Declarations
Internal declarations are instructions that the compiler adds for itself, usually during the compilation process. These instructions are usually related to memory allocation and optimization. Internal declarations can range from declarations related to memory management and garbage collection, to instructions related to performance optimization.
Types of Statements that a Compiler Does Not Consider
Compilers will not consider certain types of statements, such as macros, in-line comments, and multi-line comments.
Macros
Macros are functions or other statements that have been set up to perform specific operations when triggered. They are usually used in situations where the same operation needs to be performed multiple times. However, compilers are unable to process these types of statements and any code written using macros will be ignored by the compiler.
In-Line Comments
In-line comments are comments that are written in the code and will not be compiled. They are helpful as reminders or notes to the programmer, but they are ignored by the compiler and will not be processed.
Multi-Line Comments
Multi-line comments are also ignored by the compiler. They are similar to in-line comments, but they are written over multiple lines of code and are also ignored by the compiler.
Errors to Look Out For
When writing code, ensure that you are aware of the types of statements that compilers will and will not consider. A common error to look out for is mistakenly including a macro in your code instead of a function. This will lead to the compiler ignoring the code, so always make sure to double check your code for any macros that might have been accidentally included.
Another error to look out for is mistyping variable or function names. Compilers are very strict about syntax, so ensure that you double check your code for typos.
FAQ
What is a Compiler?
A compiler is a program that converts code written in a high-level programming language such as C++ or Java into machine code that can be run on the computer. A compiler is an essential tool for any software developer as it can take complex and difficult to read source code and create easy-to-understand and easy-to-execute machine code.
What Types of Statements can be Considered by Compilers?
Compilers will typically consider two types of statement: external declarations (such as function names, variables, classes, and interfaces) and internal declarations (such as instructions related to memory allocation and optimization).
What Types of Statments are Ignored by Compilers?
Compilers will usually ignore macros, in-line comments, and multi-line comments.
What are Common Errors to Look Out For when Writing Code?
When writing code, be aware of the types of statements that compilers will and will not consider. Common errors to look out for include mistakenly including a macro in the code, incorrectly typing variable and function names, and not double-checking for typos.
What is the Best Way for Software Developers to Avoid Making Mistakes?
The best way for software developers to avoid making mistakes is to double check any code written and to read up on the types of statements the compiler will and will not consider. It is also important to be mindful of typos and to familiarize yourself with the language of the coding environment you are using.