C ++中的指针变量和引用变量之间有什么区别？

问题：

I know references are syntactic sugar, so code is easier to read and write. 我知道引用是语法糖，因此代码更易于读写。

But what are the differences? 但是有什么区别呢？

Summary from answers and links below: 以下答案和链接的摘要：

A pointer can be re-assigned any number of times while a reference cannot be re-assigned after binding. 可以多次分配指针，而绑定后不能重新分配引用。
Pointers can point nowhere ( NULL ), whereas a reference always refers to an object. 指针不能指向任何地方（ NULL ），而引用始终指向对象。
You can't take the address of a reference like you can with pointers. 您不能像使用指针那样获取引用的地址。
There's no "reference arithmetic" (but you can take the address of an object pointed by a reference and do pointer arithmetic on it as in &obj + 5 ). 没有“引用算术”（但是您可以采用引用指向的对象的地址，并像&obj + 5那样对它执行指针算术）。

To clarify a misconception: 为了澄清一个误解：

The C++ standard is very careful to avoid dictating how a compiler may implement references, but every C++ compiler implements references as pointers. C ++标准非常小心，避免指出编译器如何实现引用，但是每个C ++编译器都将引用实现为指针。 That is, a declaration such as: 也就是说，这样的声明：
int &ri = i;
if it's not optimized away entirely , allocates the same amount of storage as a pointer, and places the address of i into that storage. 如果尚未完全优化 ，则分配与指针相同的存储量，并将i的地址放入该存储中。

So, a pointer and a reference both use the same amount of memory. 因此，指针和引用都使用相同数量的内存。

As a general rule, 作为基本规则，

Use references in function parameters and return types to provide useful and self-documenting interfaces. 在函数参数和返回类型中使用引用，以提供有用的自记录接口。
Use pointers for implementing algorithms and data structures. 使用指针来实现算法和数据结构。

Interesting read: 有趣的读物：

My all-time favorite C++ FAQ lite . 我一直以来最喜欢的C ++常见问题lite 。
References vs. Pointers . 参考与指针。
An Introduction to References . 参考文献简介。
References and const . 参考和const 。

解决方案：

参考一： https://stackoom.com/question/Ex9/C-中的指针变量和引用变量之间有什么区别
参考二： https://oldbug.net/q/Ex9/What-are-the-differences-between-a-pointer-variable-and-a-reference-variable-in-C

来源：oschina

链接：https://my.oschina.net/stackoom/blog/3210516

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