object-reference

I am wondering how to store a reference of an object inside of another object, and also set that reference as a private property. Example (pseudo-code): class foo { public: int size; foo( int ); }; foo::foo( int s ) : size( s ) {} class bar { public: bar( foo& ); private: foo fooreference; }; bar::bar( foo & reference ) { fooreference = reference; } foo firstclass( 1 ); bar secondclass( firstclass ); As you may be able to see, I just want to be able to store the reference of foo inside this bar class. I know how to simply bring it into a method and use it just in the scope of that method, but

What is the best way to determine whether an object reference variable is null ? Is it the following? MyObject myObjVar = null; if (myObjVar == null) { // do stuff } Yes, you are right, the following snippet is the way to go if you want to execute arbitrary code: MyObject myObjVar; if (myObjVar == null) { // do stuff } BTW: Your code wouldn't compile the way it is now, because myObjVar is accessed before it is being initialized. The way you are doing is the best way if (myObjVar == null) { // do stuff } but you can use null-coalescing operator ?? to check, as well as assign something var obj =

I'm curious to know how C# object references are represented in memory at runtime (in the .NET CLR). Some questions that come to mind are: How much memory does an object reference occupy? Does it differ when defined in the scope of a class vs the scope of a method? Does where it live differ based on this scope (stack vs heap)? What is the actual data maintained within an object reference? Is it simply a memory address that points to the object it refers to or is there more to it? Does this differ based on whether it is defined within the scope of a class or method? Same questions as above, but

-(UserDetail *)functionCheck :(NSString *)str { UserDetail *d2=[[UserDetail alloc] init]; NSLog(@"check address::::::> %p",&d2); d2.auth_token=str; return d2; } whenever i am calling functionCheck() function print same address check address::::::> 0xbfffd500 means it allocate same address. how to deallocate UserDetail d2 object after return. d2 is a pointer to the allocated object, so what you want is to log the value of d2 , not its address &d2 : NSLog(@"check address::::::> %p", d2); // remove the & ! ( &d2 is the address of the local stack variable, and that may be the same for each call.)

In MyApp.something.BigObject I have a memory expensive object and I like to do this var theObject = MyApp.something.BigObject; . My question is would that take up double the memory or not? The "equals sign" is the assignment operator. If the RHS is an object, then a reference is assigned to the LHS, it does not clone or copy the object. So given: var obj = {}; var b = obj; both obj and b reference the same object. 来源： https://stackoverflow.com/questions/7467335/does-javascript-equal-sign-reference-objects-or-clones-them

Beware: I'm not trying to compare if the characters are equals. Because I know how to use the String.equals() method. This question is about String reference I was studying for the OCA exam when I started to learn about the class String and it properties as immutability, etc. According to what I read or may understand about String pool is that when a string is created Java stores this object on what they call String pool and if a new string is created with the same value it is going to make reference to the string on the String pool except is the case we use the new keyword as this creates a