Compiler

Computer is a programmable machine which executes programs. Programs are written in some programming languages. But the computer only understood machine language.  

         Machine languages are almost impossible for humans to use because they consist entirely of numbers. Programmers, therefore, use either a high-level programming language or an assembly language.

        An assembly language contains the same instructions as a machine language, but the instructions and variables have names instead of being just numbers. So, Before a high level language programs can be run, it first must be translated into assembly language/ machine language in which it can be executed by a computer. The program that do this translation are called compilers.

       So we can say that " A compiler is a program that translates a source program written in some high-level programming language (such as Java) into machine code for some computer architecture (such as the Intel Pentium architecture). The generated machine code can be later executed many times against different data each time. "