Undefined Behavior

Why would you want to allow undefined behavior, as opposed to always crashing for example? Like isn’t predictability desirable?

The reasons are rooted in the design goals of these languages, including performance, flexibility, and backward compatibility.

• By not requiring specific behavior in certain scenarios, compilers are free to generate the most efficient code possible. If every potential error or misuse of the language had to result in a program crash or defined behavior, compilers might need to insert additional checks and balances that could degrade performance.