Compiler , Interpreter , Linker , and Loader ?

Compiler :

A compiler is a special type of program that transforms the source code written in a programming language (the source language)in to the machine language , which uses only two digits _0 and 1(the target language). The resultant code is 0s and 1s is known as the object code. The object code is used to create an executable program.

   Therefore , a compiler is used to translate the source code from a high-level programming language to a lower level language(e.g., assembly language or machine code). The work of  a compiler is only to translate human readable source code in to computer-executable machine code.

    Interpreter :

    like the compiler , the interpreter also executes instructions written in a high-level language. Basically, a program written in a high-level language can be executed in any of the two ways-by compiling the program or by passing the program through an interpreter.

   The compiler translates instructions written in a high-level programming language directly in to machine language; the interpreter, on the other hand, translate the instructions into an intermediate form, which it then executes.

   Linker:

   A linker, also called link editor or binder, is a program that combines the object modules to form an executable program. In general , in case of a large program, programmers prefer to break the code in to smaller modules, as this simplifies the programming task. Eventually, when the source code of all the modules has been converted in to object code, all the modules need to be put together, which is done by the linker.

Loader: 

A loader is a special type of a program that copies programs from a storage device to the main memory, where they can be executed. Most loaders are transparent to the users.