Shulou(Shulou.com)06/02 Report--

This article mainly introduces Java how to achieve value transmission, has a certain reference value, interested friends can refer to, I hope you can learn a lot after reading this article, the following let the editor take you to understand it.

Value passing is in one function, calling another function, which contains the case of parameter passing. Often value passing is passing the data to another function for further processing to show the meaning of the function more clearly. There will be data transfer when the function is called, and the problems of formal parameters and arguments should also be considered, such as the following program:

Public class PassTest

{

Float ptValue

Public void changeInt (int value)

{

Value = 55

}

Public void changeStr (String value)

{

Value = new String ("different")

}

Public void changeObjValue (PassTest ref)

{

Ref.ptValue = 99f

}

Public static void main (String args [])

{

String str

Intval

PassTest pt = new PassTest ()

Val = 11

Pt.changeInt (val)

System.out.println ("Int value is:" + val)

Str = new String ("Hello")

Pt.changeStr (str)

System.out.println ("Str value is:" + str)

Pt.ptValue = 101f

Pt.changeObjValue (pt)

System.out.println ("Current ptValue is:" + pt.ptValue)

}

}

The final output of this program will be:

eleven

Hello

99f

The first 11 and Hello follow the principle of parameter passing, although the value of the parameter is changed, but the actual parameter is not changed, which is the same as in C language. So what should I do if I want to change the value of the arguments in the function? We know that in the C language, we can use the pointer variable as the parameter of the function, so that what is passed is the address where the parameter is stored, then there will be no error when changing the parameter value of the same address in the function, but there is no pointer in java, so what should we do to achieve the above approach in C language? We know that objects are considered everywhere in java, and handles are used to manipulate the activities of objects, so if we pass the handle of the object to the function, we can make them point to the same handle (that is, the address), so that we can complete the modification of the data. See the above procedure, we can know that pt is the object of the PassTest created in the main function, by passing it, you can complete the transfer of the address, in the subfunction, ref and the pt of the main function actually point to a memory unit, then modify the value of ptValue in ref, that is, modify the value of ptValue in pt, even if there is no final data return, this data will change.

Thank you for reading this article carefully. I hope the article "how to achieve value transfer in Java" shared by the editor will be helpful to everyone. At the same time, I also hope that you will support us and pay attention to the industry information channel. More related knowledge is waiting for you to learn!

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