Value passing and reference passing in Java

Figure out the concept of the two first.

Pass by value: means that when a parameter is passed to a function, the function receives a copy of the original value. Therefore, if the function modifies the parameter, only the copy is changed, and the original value remains unchanged.

Pass by reference: means that when a parameter is passed to a function, the function receives the memory address of the original value instead of a copy of the value. Therefore, if the function modifies the parameter, the original value in the calling code changes accordingly.

Function parameters:

1. The original data type is passed by value.

 Public class Test {    publicstaticvoid  main (string[] args) {        int i=1 ;        Change (i);        System.out.println (i);    }     Private Static void Change (int  var) {        //  TODO auto-generated method Stub        var=-var;    }}

Output: 1

2, the object is to pass the reference

 Public class Test {    publicstaticvoid  main (string[] args) {        person person = New Person ();        Person.i=1;        Change (person);        System.out.println (PERSON.I);    }     Private Static void Change (person tmp) {        //  TODO auto-generated method stub        tmp.i=100;    }}

Output: 100

Because the string type does not provide its own modified function, each operation is reborn as a string object, so it should be treated in a special way. Can be considered as a pass value.

done!

Value passing and reference passing in Java