c++ - Allocating memory using new returns same memory address -

class abc  {     int x ; }; int main() {     abc *a = new abc ;     cout<< static_cast<void*>(a) << endl ;     delete ;     cout<< static_cast<void*>(a) << endl ;     abc *b = new abc ;     cout<< static_cast<void*>(b) << endl ;     delete b ;     cout<< static_cast<void*>(b) << endl ;        return 0;  }  

why prints same address , though deleted old memory .
assign null after deletion , prints same address.

even address of , b same .

real time scenario :

function1 ->    arr[p] = new x   ptr1 = arr[p]   using ptr1   function2 ->    ptr2 = arr[p]   delete ptr2   arr[p] = new x ( new data)  

in real scenario ptr1 should invalidated since compiler assign same address to
arr[p] in function2 ptr1 still works .

why should not happen? once you've deleted memory @ particular address, memory manager @ liberty re-use address next time ask new memory. indeed common optimisation used memory managers. keep track of freed blocks , hand them next client requests block of size.

another way @ consider happen if freed addresses never re-used. if happen eventually, after enough allocation/deallocation cycles, there no address space left. indeed, if re-use never happened there no point @ in deallocating memory. yes, expect when deallocate memory, memory address re-used.