Well when you programm in C/C++ following rules made by ANSI its standrad C/C++ programming.
+ point is that most compilers today follow ANSI standard...
Older Compilers like Turbo C/C++ does not folllow ANSI standard... so it creates problem when you try to execute standard C/C++ programs...
For example ANSI standard doesn't support getch() function and conio.h library.
I can write on and on.. but my hands dont allow me to do that... Just search Wikipedia for ANSI C and you will get all answers.