"I am curious why you say cost-free." What's the cost? It's an optional feature. "Using std::vector/array/string::at would literally eliminate buffer overflow

"I am curious why you say cost-free." What's the cost? It's an optional feature. "Using std::vector/array/string::at would literally eliminate buffer overflows and yet programmers aren't generally using this style." C programmers don't use that because it doesn't exist in C. "I would love it if I could prove to my colleagues that mandatory bounds-checking would not result in a noticeable performance loss" Did you read his article? There's nothing in it about mandatory bounds-checking.