Explained: Difference Between Compiler, Interpreter and Assembler

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When humans want to express their feelings, thoughts, and ideas to other humans we communicate through languages. In the same way, in the case of computers, we need languages to communicate with the computer - these languages are called programming languages. But we need a language translator in between because the computer understands only machine language (in the form of 0s and 1s) and it is hard for us to give instructions directly in machine language. Thus, we use language processors/translators. These are special translator system software used to convert the programming languages into machine code.

Compiler, Interpreter, and Assembler are types of language processors that convert programming languages to machine language (binary code). Compilers and interpreters are used to convert High-Level Language into machine language. Assemblers are used to convert Low-level Language or Assembly Language Code into Machine Language (Binary code). Let us understand about these in detail. 

Find out here how machine language differs from assembly language. 

What do you need to know about Compilers?

A compiler is a translator program that converts source code written in a high-level language like Java, C++, etc. to equivalent machine language in one go. 

It converts the entire program to executable object code if the entire program is Error-free Code. However, if there are errors in the program the compiler highlights them at the end of the execution of the entire program, and then the errors must be removed for successful compilation of source code.

It converts the source program to object code (combination of binary numbers) which can be stored and we can run it each time we need to execute the program. Therefore, it eliminates recompilation.

At the same time, due to the generation of the intermediate file, it takes up a lot of memory as compared to other language processors. Compilation as a whole process is done in the following phases - lexical analyzer, semantic analyzer, syntax analyzer, intermediate code generator, code optimizer, symbol table, and error handling.

Examples of Compilers are- Clang, GCC, javac, etc.

Advantages of Compiler

• It produces an executable file that can run without the need for source code.
• It is relatively faster than other language processors.
• Using a compiler is more secure because the actual source program can be hidden which makes it private and secure.
• The machine code of the executable file is native to the machine which makes the compiler well optimized.

Disadvantages of Compiler

• Debugging (removing errors) is relatively tough.
• It requires a lot of memory for producing an Object File.
• The source code needs to be recompiled every time there is a change in the code.
• After the removal of errors in our code, it needs to be recompiled.

What do you need to know about Assembler?

It is a translator program that converts assembly language or low-level programming language to machine code.

It was the first interface through which communication between machines and humans became possible.

Assembly language or low-level language is where we use mnemonics (instructions, in place of machine language. Assembly language is dependent on the machine which implies that the mnemonics are also dependent on the architecture of machines. 

Assembler works in two different phases over the given input-first phase and second phase.

Examples of assemblers are- GNU, GAS, etc.

Advantages of Assembler

• It is a very fast translating system software.
• It is as efficient as the machine language.
• Developing assemblers for translating is easier as compared to compiler and interpreter.
• Assemblers are used in computer forensics, brute force hacking, etc. where it is important to determine exactly what is going on.

Disadvantages of Assembler

• Lower-level machine language is difficult to understand and code.
• It changes with the architecture of machines.
• It is difficult to debug.
• We have to write different assembly codes for 8-bit, 16-bit, 32-bit, and 64-bit machines which is a tedious task and difficult to maintain.

What do you need to know about Interpreter?

It converts source programs written in High-Level Programming language into machine code line by line, which means it executes one single line at a time into machine language.

If there is an error in the program the interpreter terminates its translation process and proceeds for execution only when the error is removed. This process continues till the interpreter reaches the end of the program. 

In the case of an interpreter, each line is converted and executed simultaneously. As a result, it requires less memory space as compared to the compiler.

Examples of Interpreters: Python Interpreter, Ruby Interpreter, LISP, APL, etc.

Advantages of Interpreter

• It is easy to find and debug errors from the code/source program.
• As there is no Intermediate object Code, there is less memory consumption.
• Interpreters give execution control to programmers as they can see their code running line by line.
• It can be easily used between different platforms.
• An interpreter is good for fast debugging.

Disadvantages of Interpreter

• It takes time to convert and execute the instructions line by line.
• It is not good for large programs.
• It is less secure for privacy because we need to share the actual program.
• To run the code on another machine, it is required that the interpreter be installed on the machine.

Difference Between Compiler, Interpreter, Assembler 

Assembler vs Compiler

Compiler vs Interpreter

Why is a Compiler better than Assembler and Interpreter?

The most widely used language translator among the three is a compiler. Compilers are preferred over assemblers and interpreters because of various reasons:

• Compilers translate and execute the code faster than assemblers and interpreters.
• The compiler converts the code into an Object file which can be used whenever we need to execute the program, therefore it eliminates the need to re-compile.
• All the errors are found and displayed together at the end.

Summing Up

All three of the language processors are used to convert programming languages into equivalent machine code. Compilers and interpreters convert High-Level languages whereas an Assembler is used to convert Low-Level language.

Find out the difference between high-level and low-level programming languages here. 

Nowadays, most of the languages like Java and C++ are converted using a compiler whereas Python uses an interpreter. The use of an assembler is very rare and it is mostly only used by computer experts and hackers. 

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