What is the difference between programming languages that require pre-compilation and those that are executed directly by an interpreter?

Programming languages that require pre-compilation convert source code into machine code or intermediate bytecode before running the program. This allows the program to execute faster, as the code is already prepared for execution by the processor or virtual machine.

Interpreted languages execute source code directly using an interpreter, which reads and executes commands one by one during runtime. This is usually slower but offers flexibility and debugging convenience.

Main differences:

• Compilation:

  • Converts all code in advance.
  • Fast execution.
  • Errors are detected at compile time.
  • Examples: C, C++, Swift.

• Interpretation:

  • Executes code line by line during runtime.
  • Slower execution.
  • Allows dynamic code modification.
  • Examples: Python, JavaScript.

Some languages use a mixed approach, for example, Java is first compiled into bytecode, which is then executed by a virtual machine with JIT compilation for performance enhancement.

Example of compilation and interpretation:

// Java: compilation into bytecode
public class Hello {
    public static void main(String[] args) {
        System.out.println("Hello, world!");
    }
}

Then, the bytecode is executed by the JVM — an interpreter with JIT compilation.