C is the combination of both low level (assembly) and high-level programming languages; also, it can be used to write an application and interact with low-level system memory and hardware. It can be written on practically any operating system and even works in most handheld devices
The C programming language is a procedural and general-purpose language that provides low-level access to system memory. A program written in C must be run through a C compiler to convert it into an executable that a computer can run. Many versions of Unix-based operating systems (OSes) are written in C and it has been standardized as part of the Portable Operating System Interface (POSIX).