C++ programming language

C++ is often considered to be a superset of C, but this is not strictly true. Most C code can easily be made to compile correctly in C++, but there are a few differences that cause some valid C code to be invalid or behave differently in C++.
One commonly encountered difference is that C allows implicit conversion from void* to other pointer types, but C++ does not. Another common portability issue is that C++ defines many new keywords, such as new and class, that may be used as identifiers (e.g. variable names) in a C program.
Some incompatibilities have been removed by the latest (C99) C standard, which now supports C++ features such as line comments (//), and mixed declarations and code. On the other hand, C99 introduced a number of new features that C++ does not support, such as variable-length arrays, native complex-number types, designated initializers, and compound literals. However, at least some of the new C99 features will likely be included in the next version of the C++ standard

C programming language

C is an imperative (procedural) systems implementation language. It was designed to be compiled using a relatively straightforward compiler, to provide low-level access to memory, to provide language constructs that map efficiently to machine instructions, and to require minimal run-time support. C was therefore useful for many applications that had formerly been coded in assembly language.
Despite its low-level capabilities, the language was designed to encourage cross-platform programming. A standards-compliant and portably written C program can be compiled for a very wide variety of computer platforms and operating systems with few changes to its source code. The language has become available on a very wide range of platforms, from embedded microcontrollers to supercomputers.