The difference between calling by value and simulating calling by reference

First ：

Basic data type ：8 Kind of byte short int long (4 Kind of )  float double( floating-point )  boolea( Boolean type ) char( Character type )

Reference data type ：class,interface,array Arrays and so on

 

The reference data type must be stored in the heap , But its variable name is stored in the stack, storing a lot of information about the data in the heap

When making array names equal directly , Or let class,interface Examples created , When making the examples equal , It is equivalent to assigning its addresses together ： When the A When the example is operated , In fact, it will be right B Example to operate , The relationship between the two is similar to that in the figure C and D The relationship between

But when the basic data type is assigned , Is value passing reference ,

int A=30;

int B=A;

B=20;

For B Assignment does not affect A Value

int [] A=new int[3];// A piece of memory is created in the stack memory Store A And point to three pieces int Heap memory of array memory address

int [] B =A;

A[0]=30;// here B[0] The value of 30

// A memory is created in the stack memory to store variables B And will be A The address of is assigned to B among , Then in the heap memory ,A and B Point to and execute the same memory