A CXX file is a source code file written in the C++ programming language. C++ is a powerful, general-purpose, compiled programming language that supports multiple programming paradigms, including object-oriented, generic, and procedural programming. It was developed by Bjarne Stroustrup as an extension of the C language. Files with the .cxx extension contain human-readable text that defines classes, functions, variables, and other programming constructs. These files are typically compiled by a C++ compiler (such as GCC, Clang, or Microsoft Visual C++) into object code, which is then linked to create an executable program or a library. The .cxx extension is one of several common extensions used for C++ source files, alongside .cpp, .cc, .c++, and sometimes .C (uppercase C). It is often used to explicitly denote a C++ source file, particularly in projects where C and C++ files might coexist, to avoid ambiguity with C source files (which typically use the .c extension). C++ is widely used for developing operating systems, game engines, high-performance applications, embedded systems, and various other software.