Does new always allocate on the heap in C++ / C# / Java

Question

My understanding has always been, regardless of C++ or C# or Java, that when we use the new keyword to create an object it allocates memory on the heap. I thou

Answer 1

In Java and C#, we don't need to allocate primitive types on the heap. They can be allocated on the stack ( not that they are restricted to stack ). Whereas, in C++ we can have primitive as well as user defined types to be allocated on both stack and heap.

Answer 2

Java 7 does escape analysis to determine if an object can be allocated on the stack, according to http://download.oracle.com/javase/7/docs/technotes/guides/vm/performance-enhancements-7.html.

However, you cannot instruct the runtime to allocate an object on heap or on stack. It's done automatically.

Answer 3

In c#, a class always lives on the heap. A struct can be either on the heap or stack:

• variables (except captures and iterator blocks), and fields on a struct that is itself on the stack live on the stack
• captures, iterator blocks, fields of something that is on the heap, and values in an array live on the heap, as do "boxed" values