Understand memory storage for various data types and simple classes.

The base data type. int, char short.

int A;
The A tag represents the data for an address, and the data type is int. So it accounts for 4 bytes.
A=3;
Give the label of the base data type straight. It is equal to the data of the address represented by the tag.
Since a tag represents the data of an address, its address is obtained using &A.
&a:0x22ff1c:03 00 00 00
& (&a) will be wrong because &a is not somewhere in memory.

The array type.

int a[3]
First, a[0],a[1],a[2] is as understanding as the basic data type.
The a[0] tag represents the data for an address, and the data type is int. So it accounts for 4 bytes.
So ibid & (a[0]),& (a[1])
& (A[0]): 0x22ff04

You can no longer need to know the extra knowledge here. Data and addresses are available.

Originally a does not have any meaning in itself.

However & (A[0]), the representative's first address is too large for the program. Pass the argument, return, etc.
So use A to represent & (A[0]), A+1 Representative & (A[1])
But a is an address constant. Many situations want to change a to other straight, so that the pointer, the equivalent of a this address constant into memory, with a (type *) type to represent.

is the pointer type. An inaccurate understanding is actually a 2-byte address that holds the first address of a mutable array.

Pointer type.

char * a= "ag!";
First, a[0],a[1],a[2], *a, * (a+1), * (a+2) and basic data types are understood as well.

So Ibid. & (A[0]),& (a[1]) A, a+1

The *a tag represents the data for an address, which accounts for 4 bytes of data. The first address is stored.
The definition must be (type * a). Because only the first address is not. You must know what type is stored. How many bytes are taken to form a single data.

A label and array type Label class, which represents the address of the first data.
c:0x403024

&a represents the address at which the first address is stored.

Class

Class A;
The meaning of the label of the class and the array class. Just use it without subscript.
A.name A.sex is as understanding as the basic data type.
So
&a.isbn:0x22ff18
In the case of a simple class, the address of the first data is the address of the class
&a:0x22ff18

The straight type does the row parameter.
void Change (Sales_item b)
The member variables of the class are all put into the stack as arguments. Of course, the out-of-function object is not modified.

Movb $0x62,0x18 (%ESP)
0X00401347MOVL $0x3,0x1c (%ESP)
0x0040134fmov 0x18 (%ESP),%eax//
0x00401353mov 0x1c (%ESP),%edx
0x00401357mov%eax, (%ESP)//class data member into the stack
0x0040135amov%edx,0x4 (%ESP)//class data member into the stack
0x0040135ecall 0x40136a <change (Sales_item) >

Reference type
void Change (Sales_item &b)

0x00401342movb $0x62,0x14 (%ESP)
0X00401347MOVL $0x3,0x18 (%ESP)
0x0040134flea 0x14 (%ESP),%eax//note the LEA directive. Here is the address into the stack. And the address of the first data member of a class object, which should be the address of the class.
0x00401353mov%eax, (%ESP)
0x00401356call 0x40136a <change (sales_item&) >

Understand memory storage for various data types and simple classes.