C ++函数：&号对星号 [英] C++ functions: ampersand vs asterisk

问题描述

假设你有一个修改变量的函数。

Let's say you have a function that modifies a variable.

如果你这样编写： void myfunc（int * a）或像这样 void myfunc（int& a）？

Should you write it like this: void myfunc(int *a) or like this void myfunc(int &a)?

用 myfunc（& b）调用函数，因此调用者知道 b 将被修改，后者更短，可以简单地用 myfunc（b）调用。那么哪个是更好的使用？

The former forces you to call the function with myfunc(&b) so the caller is aware that b will be modified, but the latter is shorter and can be called simply with myfunc(b). So which is better to use? Is there something else I'm missing?

推荐答案

指针（即'*'）应该用于传递 NULL是有意义的。
例如，您可以使用NULL来表示需要创建特定对象，或者不需要执行特定操作。
或者如果它需要从非C ++代码调用。 （例如，用于共享库）

Pointers (ie. the '*') should be used where the passing "NULL" is meaningful. For example, you might use a NULL to represent that a particular object needs to be created, or that a particular action doesn't need to be taken. Or if it ever needs to be called from non-C++ code. (eg. for use in shared libraries)

例如。 libc函数 time_t time（time_t * result）;

eg. The libc function time_t time (time_t *result);

如果 result 不为NULL，当前时间将被存储。但如果 result 为NULL，则不执行任何操作。

If result is not NULL, the current time will be stored. But if result is NULL, then no action is taken.

t需要使用NULL作为有意义的值，然后使用引用（即'&'）可能会更少混淆 - 假设是您的项目使用的约定。

If the function that you're writing doesn't need to use NULL as a meaningful value then using references (ie. the '&') will probably be less confusing - assuming that is the convention that your project uses.

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