Pointers

C# allows use of pointers and corresponding pointer arithmetic. Pointers and pointer-arithmetic are potentially unsafe in a managed environment as they can be used to bypass the strict rules for object access. C# addresses that concern by requiring that code blocks or methods that use the feature be marked with the unsafe keyword, so that all clients of such code can be aware that the code may be less secure than otherwise. The compiler requires the /unsafe switch to allow compilation of a program that uses such code. Generally, unsafe code is either used to allow better interoperability with unmanaged APIs or system calls (which are inherently "unsafe"), or for performance reasons. Java does not allow pointers or pointer-arithmetic to be used.