What is Editor, Preprocessor, Compiler, Assembler?

 Tools required for any High Level Language Program            
             For any program in High Level Language, we require following applications(softwares, tools).

1. Editor
2. Preprocessor
3. Compiler
4. Assembler
5. Linker
6. Loader

1. Editor
            Editor is a tool used to write a program. e.g. gedit, Notepad, Wordpad, MS Word etc.

2. Preprocessor
            Preprocessor expands the program. It adds preprocessor directives definitions in the program wherever they are called. e.g. header files, constant definitions, macros etc.

3. Compiler
            It is important application. It converts high level language program to low level language program(Assembly Language/Machine Language). It includes six phases, that we will see in the next part of this post.

4. Assembler
            It is a tool, which accepts assembly language code and converts it into the machine language(executable) code. This executable code has relocatable logical addresses.

5. Linker
            It is the tool which links program to the global variables.

6. Loader 
            Loader loads the program from secondary storage(Hard disk, usb storage etc.) to the main memory(RAM) to get executed by the processor. Loader uses the relocatable logical addresses and save the executable code into the actual address space in the main memory.