Compilers and Interpreters

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Compilers and Interpreters

A programming language is a tool for creating computer programs that run on computers. To understand how programming languages work, you have to know about compilers and interpreters. Compilers and interpreters translate human-readable code into machine-readable code, but they work differently.

Understanding the Difference


Computer programs that translate human-readable code into machine-readable code are called compilers. The compiler generates machine-readable code and stores it in a file that can be executed without the compiler being around. This means the code can be executed on any computer that supports the platform on which it was compiled, regardless of whether or not it has a compiler installed.

In a compiler, all the source code is converted into machine code before it’s executed. It’s called a “compile cycle.” During the compile cycle, the compiler checks the source code for syntax and semantic errors. It halts and gives an error message if any are found. A machine-readable file that can be executed will be generated by the compiler if the source code is error-free.

Advantages of Compilers

1. It takes less time to execute.

2. The machine code generated is platform-independent.

3. Better error handling: Compilers usually do syntax and semantic checks during compilation. This helps catch errors early and saves time compared to finding and fixing errors during runtime.


On the other hand, interpreters translate human-readable code into machine-readable code line by line. In order for the machine-readable code to run, the interpreter needs to be present during execution. This means the code needs to run on a computer with the interpreter installed.

The interpreter reads the source code line by line and executes each line immediately If an error is found, the interpreter stops and gives a message to the user. This allows for quick and easy debugging, since errors can be caught right away.

Advantages of Interpreters

1. Debugging and modifying the code is easy.

2. Code can be executed right away without compiling.

3. Interpreters are usually platform-independent and can run the same code on different operating systems and hardware architectures.

The choice between a compiler and an interpreter depends on the project’s requirements. Compilers are best suited for projects that need fast execution times and protection of the source code, whereas interpreters are best suited for projects that require quick debugging and code modification.

Working of Compilers and interpreters : Step by Step

Working of Compilers:

1. Compilers read the source code.

2. Code is checked for syntax and semantics by the compiler.

3. An error message is displayed if the compiler encounters an error.

4. The compiler generates machine code if there are no errors.

5. An executable file is saved with the machine code.

6. Results are displayed after running the executable file.

Working of Interpreters:

1. Source code is read by the interpreter.

2. Interpreters translate and execute code line by line.

3. When an error occurs, the interpreter stops and displays an error message.

4. The code is executed if there are no errors, and the results are shown.

5. Every line of code follows the same process.

Which one is best ? Interpreters OR compilers

Interpreters and compilers work differently depending on the use case.

Interpreters are best for:

1. Rapid development process where you test and modify code quickly.

2. interactive situations, like educational or testing situations.

3. process of writing code and executing it in small chunks over time.

Compilers are best for:

1. Applications that need to run fast and perform well.

2. Applications where security is a concern, since machine code is harder to reverse engineer than interpreted code.

3. Platform-independent applications since compiled code runs on any machine that supports the platform it was compiled for.

The general rule is that compilers are better suited to production environments because of their performance and security, while interpreters are better suited to development and testing environments because of their ease of use and immediate feedback.

Just-in-time (JIT) Compiler

Just-in-Time compiler (JIT) compiles code at runtime instead of ahead of time as a traditional compiler does. JIT compilers compile code into machine code just before it is executed. This can result in improved performance compared to interpreting or compiling code ahead of time, because it uses information about the runtime environment to optimize the compiled code to be optimized for specific hardware and software environments.

A JIT compiler is commonly used in a virtual machine to run code written in high-level programming languages, such as Java. Dynamic languages like JavaScript are also supported by JIT compilers, which can make a big difference in performance. They’re also used in optimizing compilers, which lets you optimize code that’s already been compiled in advance.

Advantages of JIT Compiler

Compared to traditional compilers, JIT compilers have a lot of advantages. They can use runtime information to generate optimized machine code, so they can be more efficient. The compiler can also be updated at runtime to support new hardware or features, so it’s more flexible and easier to modify. In addition, JIT compilers reduce the size of compiled code by only generating code for the part of the program that is actually executed, rather than generating code for the whole thing.

In addition to providing detailed information about the code generated, JIT compilers are also capable of reducing code execution latency, since they can compile and execute code more quickly than traditional compilers. By compiling code just before it is executed, JIT compilers make it harder for attackers to exploit vulnerabilities in the code compiled before it is executed, thus reducing the risk of security vulnerabilities.

In general, JIT compilers can improve code performance and flexibility, especially in dynamic environments and virtual machines. Using JIT compilers has some trade-offs, like increased complexity and the need for more memory, so you should think about them carefully when and how you use them.


Compilers and interpreters translate human-readable code into machine-readable code. Compilers generate machine code that can be executed without the compiler being present, and they usually check syntax and semantics during the compile cycle to catch errors early on. Code is translated line by line and executed immediately by interpreters, which makes debugging and modifying code easier. It depends on the project’s requirements whether you need a compiler or an interpreter. Compilers are good for fast execution times and source code protection, whereas interpreters are good for quick debugging and code modification.

Another type of compiler is just-in-time (JIT) compilers, which compile code at runtime instead of beforehand. They’re easier and more flexible to edit than traditional compilers and can generate optimized machine code using runtime information. Code execution latency can also be reduced and compiled code size is smaller.

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