Analysis of function parameter passing features in C, java, and php

I have never had time to write my own understanding of pointers in C. Although this article has little to do with pointers, but for some people who want to have a deep understanding of the pointer, it is really necessary to take a look. I was particularly disgusted with the comparison between "transfer" and "reference transfer? I really want to say, who is defining "transfer" and "Introduction "?

I have never had time to write my own understanding of pointers in C. Although this article has little to do with pointers, but for some people who want to have a deep understanding of the pointer, it is really necessary to take a look. I was particularly disgusted with the comparison between "transfer" and "reference transfer? I really want to say, who is defining "transfer" and "Introduction "?

Zookeeper

I have never had time to write my own understanding of pointers in C. Although this article has little to do with pointers, but for some people who want to have a deep understanding of the pointer, it is really necessary to take a look.

I was particularly disgusted with the comparison between "value transfer" and "reference transfer?

I really want to say, who is defining the meaning of "value transfer" and "reference transfer?

However, most people in today's education have said this, and I have not proposed it to the teacher. I have contributed to my understanding and hope to help new friends.

First of all, I would like to advise those friends who are still struggling with the difference between "value transfer" and "reference transfer". Please do not worry about it. I will give you some advice here, in the traditional sense, the "value transfer" and "reference transfer" in the instructor's mouth actually refer to "passing when a parameter is not a pointer type" and "passing when a parameter is a pointer type "...

/*********************************
* About parameter transfer.
* In C, all parameters are transmitted using the value transfer method.
* Similar situations such as int a and Person p...
* (Note that I don't want to pay too much for it. Please note the meaning of direct modification that I want to express)
* 1: directly modifying the form parameter will not affect the actual parameter in any case.
* 2: directly modifying the members of the form parameter cannot affect the members of the actual parameter.
* 3: modifying the content pointed to by the pointer type member of a form parameter can affect the content pointed to by the pointer type member corresponding to the actual parameter...
* In C, there is also a parameter form called reference. I hope you can automatically understand the term 'quot' in different places...
* Person & p, int &
* 1: You can modify the members of an actual parameter by modifying the form parameter.
* 2: You can directly modify parameters to modify the actual parameters.
* (Note the second point is that neither java nor php can do it completely) ==> note: the reason for bringing a 'complete' is that php is barely able to do part of it...
*
* Java
* For java, everything is referenced.
* 1: The actual parameter itself cannot be changed by changing the form parameter.
* 2: You can change the members of the actual parameter by changing the members of the formal parameter.
* 3: in short, formal parameters and actual parameters actually reference the same object.
* To achieve the effect of not referencing the same object, you need to use the clone method. However, note that the clone method is displayed and called automatically.
* The clone method will never be related to parameter passing.
* (It doesn't matter how you understand common type data. Even if you understand it by reference, normal type variables do not have members.
* The formal parameters do not have any influence on the actual parameters.
*)
*
* Php is more similar to java
* For php. Similar to java.
* 1: first of all, for common data types, there is no such thing as a member. Therefore, formal parameters do not have any influence on actual parameters.
* 2: similar to java, a class object is a reference value by default.
* Similar to java
* 1: The actual parameter itself cannot be changed by changing the form parameter.
* 2: You can change the members of the actual parameter by changing the members of the formal parameter.
* 3: in short, formal parameters and actual parameters actually reference the same object.
*
* Difference. The above features of php are similar to those of java, but one thing is that java does not, that is &.
* First, compare the functions of C and php with those of C.
* Achieved the goal :{
* 1: You can modify the members of an actual parameter by modifying the form parameter.
* 2: You can directly modify parameters to modify the actual parameters.
*}
* However, php is not completely the same as c...
* Here we will explain that the so-called 'incompleteness 'is actually an incomplete implementation mechanism, and it is almost the same in actual use...
*
* Why is the implementation different?
* C references. The actual format parameter and actual parameter can be understood as one thing.
* Php cannot understand this.
* It can be considered that php is constantly maintaining the relationship between the two, resulting in consistency between the two at all times.
* That is, the two are not the same memory. When one is to be destroyed, the other is not destroyed.
* That is, when the unset function is used, only the association between the two is canceled.
*
*/