blocks|key|1171381|text|变量实际上不做任何工作。取而代之的是，程序可以处理变量。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1171382|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

A variable actually does not do any work. Instead, a program may work upon variables.

blocks|key|957058|text|考虑以下定义|type|unstyled|depth|inlineStyleRanges|entityRanges|data|957059|char+*string="abc";
int+b+=+10;
int+*bptr+=+&b;|code-block|syntax|javascript|957060|我稍微简化了一下，使用十进制值，变量(名称)是地址的占位符，在这些地址中存储具体的值。|957061|Adr++content
1000+a+b+c+0++++//+"abc"+:+string+literal+'\0'+terminated+
1004++++1000++++//+*string:+pointer+to+string+(address+1000)
1008++++++10++++//+b+=+10+:+integer+value
1012++++1008++++//+*bptr++:+pointer+to+&b+|957062|例如，通过使用printf("%25s\n“，string+)；您不想复制整个字符串，而是给出字符串开始的地址(通过引用调用)。|957063|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

Consider the following definitions

<pre><code>char *string="abc";
int b = 10;
int *bptr = &amp;b;
</code></pre>

I simplify this a little bit and use decimal values, the variables (names) are placeholder for adresses, at these adressess the concrete values are stored. 

<pre><code>Adr content
1000 a b c 0 // "abc" : string literal '\0' terminated 
1004 1000 // *string: pointer to string (address 1000)
1008 10 // b = 10 : integer value
1012 1008 // *bptr : pointer to &amp;b 
</code></pre>

By using e.g. printf("%s\n" , string ); you don't want to copy the whole string, rather you give the address where the string starts (call by reference).

blocks|key|957123|text|局部变量可以驻留在内存或寄存器中，也可以在程序执行的不同阶段在这两个变量之间浮动，也可以与另一个变量共享空间。编译器可以自由地为您的变量分配最有效的空间。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|957124|如果你把指针指向一个变量，那么编译器需要把这个变量放入内存，这样它就有了一个唯一的地址。但是，如果您从不将指针指向它，那么您的变量可能会保留在它自己的CPU寄存器中。或者，如果您有两个局部变量，并且从未同时使用这两个变量，则编译器可以让它们占用相同的内存或CPU寄存器。|957125|http://en.wikipedia.org/wiki/Register_allocation|offset|length|957126|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|0|1C|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|Q|8|@]|9|@$F|R|G|S|1|T]]|A|$]]|$1|H|3|-4|5|6|7|U|8|@]|9|@]|A|$]]]|I|$J|$5|K|L|M|A|$N|E]]]]

A local variable can live in memory, or in a register, or it can float between the two at different stages of program execution, or it can share space with another variable. The compiler is free to allocate the most efficient space for your variable.

If you take a pointer to a variable then the compiler needs to put that variable into memory, so that it has a unique address. But if you never take a pointer to it then your variable can might remain in its own CPU register. Or if you have two local variables, and if you never use both of them at the same time, then the compiler can have them occupy the same piece of memory or CPU register.

<a href="http://en.wikipedia.org/wiki/Register_allocation" rel="nofollow noreferrer">http://en.wikipedia.org/wiki/Register_allocation</a>

blocks|key|1171578|text|Not+Buddy指针是一组变量，为了区分它们，除了变量的数量之外，值(整数，字符)也必须不同！|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1171579|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Not Buddy
a pointer is a set of variables, and to differentiate them, besides the number of variables, values (integer, character) has to be different!

blocks|key|957232|text|我知道你已经接受了一个答案，但这并不能直接回答你的问题...这是为了给你启迪，如果你想读的话。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|957233|How+does+automatic+memory+allocation+actually+work+in+C%2B%2B?|offset|length|957234|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/1612982/how-does-automatic-memory-allocation-actually-work-in-c/1613391#1613391^0|0|0|1M|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|O|8|@]|9|@$D|P|E|Q|1|R]]|A|$]]|$1|F|3|-4|5|6|7|S|8|@]|9|@]|A|$]]]|G|$H|$5|I|J|K|A|$L|M]]]]

I know you've already accepted an answer, and this does not directly answer your question... this is for your edification, if you desire to read it.

<a href="https://stackoverflow.com/questions/1612982/how-does-automatic-memory-allocation-actually-work-in-c/1613391#1613391">How does automatic memory allocation actually work in C++?</a>

blocks|key|1171689|text|变量只保存它应该保存的值。如果它是一个指针，它将保存一个内存地址；如果它是一个整数，它将保存一个整数值；如果它是一个浮点数，它将保存一个浮点数……|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1171690|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

A variable just holds the value it is supposed to hold. If it is a pointer, it will hold a memory address, if it is an integer it will hold an integer value, if it is a float, it will hold a floating point number...

How does a variable in C/C++ work?

I mean, a pointer stores an address from a variable and then you have to dereference it to access the object to which it refers, so I think that a variable is a pointer that is dereferenced automatically when used... does that make any sense?

How does a variable in C/C++ work?

编译器

C/C++中的变量是如何工作的？我的意思是，指针存储了一个变量的地址，然后你必须取消引用它才能访问它引用的对象，所以我认为变量是一个指针，当使用它时会自动取消引用...这有什么意义吗？

问C/C++中的变量是如何工作的？
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