   Run-Time problems
  I have wondered and googled,but didn't find what was I looking for.Access Violation:Do access violation occur when youtry to access (read or write) unallocated memory?And what's the uninitialized memory's value?When a program not responds:How does that work?   
  Access violations happen when you read or write to memory that the operating system has not given you permission to read or write to. Most of the time this means you're trying to do something with bogus memory. However, that's not the only time they can occur, and messing with the wrong memory may not always cause an access violation. The actual value of the memory is completely unpredictable, and depends on the actual location in memory. Some compilers will set memory to values like 0xBAADF00D or 0xF001 when in debug mode, to make it more obvious what memory is unallocated, but in reality the actual memory locations that will have such easy-to-spot values are in the minority."Program Foo is Not Responding" means that Windows has been sending messages to the program, but one or more threads haven't been erasing messages from the message queue properly. This is usually because the thread(s) are doing something else, like getting stuck in an infinite loop.   ;  Thank you very much Apoch, ratings++.And have seen that uninitialized mem values in debug is hex: 0xcccccccc.   