- A compiler is defined as a software that transforms an entire set of source code into object code and saves it as a file before executing it. Conversely, an interpreter converts and executes source code line by line without saving it and points out errors along the way.
- Compiled languages include C, C++, COBOL, and Fortran. Python utilizes an interpreter, as do JavaScript, Perl, and BASIC.
- This article details the main differences between compilers and interpreters and lists their pros and cons.
Table of Contents
What Is a Compiler?
A compiler is a piece of software that transforms source code into object code before executing it. Simply put, a high-level language is converted into machine/binary language, and this stage is required to make the program executable. This is because the only language the computer understands is binary.
As an intermediate phase, certain compilers transform the high-level programming language into assembly language, and others directly convert it to machine code. This conversion of source code into machine code is called compilation. Popular computer languages that use compilers include C, C++, COBOL, and Fortran, among others.
How does a compiler work?
The operation of a compiler can be categorized as follows:
- Source code creation: The source code is a piece of code composed in a text editor, and the file extension for the source code is ‘.c,’ if you are using a compiler with the C programming language as an example.
- Preprocessing: This source code is initially transmitted to the preprocessor, which expands it. The enlarged code will be provided to the compiler after expansion.
- Compiling: The code expanded by the preprocessor is passed to the compiler, which converts it into assembly code.
- Conversion into object code by an assembler: Using an assembler, the assembly code is transformed into object code. The object file created by an assembler has the same name as the source file.
- Linking: When a program occasionally references functions specified in other files, the linker serves a crucial role. In the compiler workflow, the primary function of a linker is to connect the object code of coding library data alongside the object code of a program.
- Execution: The executable file is the final product of the linker.
Pros and cons of a compiler
A compiler offers the following advantages:
- It operates quicker than the interpreter because the source code has already been compiled and the executable file has been generated.
- Your client does not need to install a compiler, interpreter, or third-party program to run the executable file of your shared source code.
- On all of your clients’ and any other system, executable files generated by the compiler can be launched without needing the source code. This renders your program hack-proof, protected, and confidential.
- The machine code of an executable file generated by a compiler is frequently a well-optimized, native machine command for the intended machine, resulting in accelerated execution.
However, compilers do have a few drawbacks:
- Since its code is optimized for the system on which it was executed, it could trigger system compatibility issues.
- Compilers must generate a new file, which consumes additional memory.
- After perusing the entire code, it returns all available errors at once, making it harder to locate and correct them.
- Unlike an interpreter (discussed in the following section), we cannot run the source code straight away; we must additionally launch the executable file.
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What Is an Interpreter?
The software that executes the line-by-line conversion of high-level instructions to machine-level programming is called an interpreter. If an error is detected on any line of code, the execution is halted until resolved. Errors are displayed line by line, making the correction of them simpler. However, the program requires a little more time to run successfully.
Source code lines are compiled beforehand and preserved as machine-independent codes, and this is subsequently attached at runtime and processed by the interpreter. It aids the programmer in identifying errors and correcting them before moving on to the subsequent statement.
The interpreter executes the high-level program code’s instructions. For interpreted programs, the source code is always required for processing. Consequently, they tend to execute more slowly than compiled programs. Among the most prominent programming languages, Python utilizes an interpreter. JavaScript, Perl, and BASIC are instances of other popular interpreter-led programming languages.
How does an interpreter work?
The operation of an interpreter can be broken down as follows:
- Source code creation: This step of the functionality is the same as in the case of a compiler. During runtime, however, the interpreter transforms the source code one line at a time.
- Direct interpretation: An interpreter meticulously translates a high-level language program into machine-level language.
- Source code editing: The interpreter permits program assessment and modification throughout the execution in a side-by-side window.
- Execution: Compared to the compiler, program execution is moderately sluggish since all the linking is done at runtime without a separate linker.
Pros and cons of an interpreter
Using an interpreter offers the following advantages:
- Since it scans the code line by line and sends the error notice straight away, debugging is simpler.
- Those with access to the source code can easily rectify or alter the code if necessary.
- In interpreted languages, the source code can be directly shared and executed on any machine without device incompatibility problems.
- Interpreters do not create new independent files. As a result, it does not consume additional memory.
- The source code is executed without any additional steps; it is run spontaneously.
However, it is also important to remember the following disadvantages of interpreters:
- If code execution is interrupted at any point, interpreters restart from the beginning every time the code is executed.
- The interpreter is typically more sluggish than the compiler as it scans, analyses, and transforms each line of code individually.
- A client or anyone with access to the shared source code will need an interpreter installed on their system to execute the code.
- To pass on an interpreted program with others, one must share unsecured and non-private source code.
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Compiler vs. Interpreter: 12 Key Differences
By now, the main distinction between a compiler and an interpreter is probably clear. Nevertheless, the basic differences between compilers and interpreters are listed below.
| Compiler | Interpreter | |
|---|---|---|
| Programming process | When using a compiler, the programming process is as follows:
|
When using an interpreter, the steps are as follows:
|
| Purpose of the system | The primary purpose of each program is one of the most unique distinctions between a compiler and an interpreter. While the two programs have the same objective of transforming text into machine code that a PC or system can use, their operations are a bit different.
A compiler, for instance, may convert a whole program or code collection in one go. This can simplify the translation process and reduce the number of stages necessary to complete the program. |
The time required by an interpreter to translate code statements is mostly lengthier.
This is because interpreters interpret a single line of code at a time, regardless of the number of lines or bundles in a program. Consequently, interpreters can rapidly examine every line of code written and generate new machine code. |
| Speed of operation | Execution speed is the rate at which a program converts high-level language into machine code.
A compiler typically accelerates program execution. Since the program code is already converted into machine language, its execution time is shortened. |
The time required to interpret a full program is longer than the time needed by the compiler to accomplish its task because interpreters examine each line individually. |
| Applicability and use cases | Utility refers to the optimal way for programmers to translate a high-level language using these programs.
A compiler is ideal for a production environment. To translate in these circumstances, programmers frequently employ compiled programming languages such as Java, C, C++, and C#. |
Interpreters are ideal for a software development setting. Interpreter programming languages Python, Ruby, Perl, and PHP are prime examples. |
| The sequence of program execution | When using a compiler, the execution of the program occurs autonomously from its compilation. Program execution happens only after the development of the entire program. | Interpreters operate in different capacities. Parallel to the authoring of the source code, the process of running the program is carried out line by line in the course of the interpretation steps. |
| Data capacity | Compilers are sometimes perceived as having decreased data capacity. They can take considerable time to evaluate the source code they intend to translate because they evaluate it in large datasets. Due to the intermediate object code they generate, compilers typically require additional linkage. This may demand more memory than interpreter-generated code. | Regarding data capacity, interpreters are widely regarded as more effective than compilers. This is because they do not generate intermediate code, simplifying the entire procedure by decreasing the need for linkage. Moreover, interpreters can typically assess source code rapidly since they read code line by line. |
| Error handling and debugging mechanisms | Error handling is the primary distinction between an interpreter and a compiler. This is because each form of the program has its own system to recognize and react to flaws that may occur within lines of translated code.
Typically, a compiler only provides error messages after examining every line of the program that it is attempting to translate. Although this can be useful for clustering errors, it can also increase the time required to debug and rectify programs since programmers must traverse every single piece of code. |
In contrast, an interpreter addresses each error individually. This typically indicates that an interpreter can continue deciphering a program until an error is identified.
Typically, when an interpreter detects an error, it halts all translation operations and underlines the error till the programmer repairs it. The interpreter can continue translating the remainder of the program by repeating the above process. This can be extremely useful for software developers since it can facilitate program debugging by pointing out errors as soon as they appear and holding them in place until the programmer repairs them. |
| Amount of memory needed | A compiler needs more memory space since it creates an intermediate object code. Object code is the binary code that is stored explicitly in a file. To store machine code, a compiler might want a separate memory source, such as disk storage. | Meanwhile, an interpreter requires less memory due to the absence of intermediate object code. It can seamlessly function using just the computer’s random access memory (RAM). |
| Flexibility to make changes | Utilizing a compiler can be challenging when modifying or altering program code. For programs to undergo alterations, the source code as a whole must be modified. This makes using a compiler difficult. | Comparatively, interpreters offer greater flexibility because they show errors one line at a time. This implies that a programmer can readily identify and eliminate translation errors. |
| Analysis of source code | The analysis of source code through a compiler requires considerable time, as previously discussed. However, compiled code is faster than code that’s interpreted. | An interpreter requires less time than a compiler to analyze source code. Nevertheless, interpreted code is generally sluggish because it has to read, analyze, and execute each program statement at runtime. |
| Visibility into source code | With compiled languages, source code can be kept confidential. Executables do not contain source code; therefore, if you share your program with others, they cannot access your ‘secret sauce.’ | With an interpreter, anyone with whom you share your program will have access to its source code. If you are employed by a software company, exposing your source code might render it accessible to intruders or adversaries who intend to illicitly obtain your company’s confidential information. |
| Number of steps required | Another common distinction between compilers and interpreters is how each program is processed. Compilers and interpreters convert source code into machine-readable code. However, interpreters accomplish this in a single step, while compilers require two. Before execution, a compiler converts the source code into a target program. | Interpreters simultaneously compile and execute the program. |
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Takeaway
Compilers and interpreters are both computer programs that translate code created in a high-level language, transforming it into a lower-level language or machine code that systems can comprehend. However, they operate differently and have unique applications. Even if you don’t plan to incorporate a compiler or interpreter in your next endeavor, these perspectives will help you better understand the resources you employ daily as a developer.
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