What does sub mean in C language?

Sub is not a system keyword in C language, but a legal identifier defined by the developer himself. Generally, it is used to store variables as the result of difference calculation, and it can also be used as a function name to define the function of difference calculation.

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C language is a general computer programming language, which is widely used in the bottom development. The design goal of C language is to provide a programming language that can compile and process low-level memory in a simple way, generate a small amount of machine code and run without any support of running environment.

Although C language provides many low-level processing functions, it still maintains good cross-platform characteristics. C language programs written in standard specifications can be compiled on many computer platforms, even including some embedded processors (single chip microcomputer or MCU) and supercomputers.

C language is a process-oriented computer programming language, which is different from object-oriented programming languages such as C++ and Java.

Its compilers mainly include Clang, GCC, WIN-TC, SUBLIME, MSVC, Turbo C and so on.