[ncmncm]

Simply this: if you write C code, it produces the same instructions compiling with a C or C++ compiler.

But a C compiler restricts you to the C subset. Many of the most useful features of C++ generate no extra instructions, but make the code more maintainable. There are libraries that compile to no code except exactly what you call, optimized down to exactly the circumstances of the call, wholly inexpressible in C, that you would have to open-code directly in C, gaining no benefit from the maturity of a library.

In other words, in the absolute worst case, you write the program using only C features, and get the same program. But there is never a reason to opt for the absolute worst case when you have a better choice.

[anmorgan]

Okay, I think this reply helps frame your stance much better. You are not necessarily proposing no C ever, but saying at least start a new project with a C++ compiler / IDE and if there are reasons to use C code or rules like "don't use dynamic memory allocation", when there is a substantial reason, then that is acceptable

[ncmncm]

There is no connection between C++ and dynamic memory allocation. Most of my C++ programs allocate memory at startup, then run for weeks or months (on machines with 200+ GB of RAM) never allocating ever again. C programs routinely allocate dynamic memory, except where there is reason not to; likewise C++.

So, no, there is never a reason to confine yourself to the C subset, in a new program. "for (auto e : v)" is universally better than "for (i = 0; i != N; ++i)". Zero cost, better code.

But I would never, ever suggest using an IDE, under any circumstances, for any language.