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C supports variable-length stack-allocated arrays, while C++ doesn't. So code like void f() { int x; scanf("%d", &x); // read from user

C supports variable-length stack-allocated arrays, while C++ doesn't. So code like void f() { int x; scanf("%d", &x); // read from user int numbers[x]; // dynamic } is legal C, but not C++. Also, the C "restrict" keyword doesn't exist in C++ either. Add in C's looser typing rules regarding conversions, and C and C++ are basically sibling languages at this point. Their common ancestor language being K&R-era C.

saghm 9y ago
> C supports variable-length stack-allocated arrays, while C++ doesn't. So > code like > > void f() { > int x; > scanf("%d", &x); // read from user > int numbers[x]; // dynamic > } I just pasted this in a file (and added `#include <cstdio>`) and compiled with g++, and it gave no errors or warnings and produced a *.o file, so maybe it does work?
- bstamour 9y ago
  That's because gcc supports it as an extension to C++. It's not an official part of the language, and using it in C++ code is therefore not portable across compilers/platforms.
  - saghm 9y ago
    clang++ seems to work as well. I don't have a Windows machine handy to try MSVC, though