Questions about programs that read code in one language (source language) and translate it into an equivalent program in another language (target language).
A compiler is a program that transforms source code written in a programming language (the source language) into another language (the target language).
Example: A C++ compiler transforms your C++ code into equivalent Assembly Language or Machine Code.
A rough sketch of working of compilers
Source Program (or Code) → Compiler → Target Program (or executable code)
Compilers are more generally used to translate high-level code (like C#, C++, Java) into low level or machine code.