2个愚蠢的阵列问题!! [英] 2 stupid array questions!!
问题描述
嗨大师'，
这是我的问题...
1）为什么c允许额外的，数组intialiser？这有什么优势吗？
ex：int arr [5] = {1,2,3,4,5，编译器没有给出错误！
>
函数参数？
ex：
void foo（int arr []）
{
/ *我想确定数组的大小arr在这个函数中.I
尝试*使用sizeof操作员并意识到它不会起作用
asarr将被视为指向int的指针!!!!!! * /
}
提前致谢
Hi Guru''s,
Here are my questions...
1)Why does c allows an extra "," in array intialiser?Is there any
advantage of this?
ex: int arr[5]={1,2,3,4,5,};
^^Compiler does not give error for this!
2)How to determine the size of the array which is passes as a
parameter to the function?
ex :
void foo(int arr[])
{
/*I want determine the size of the array "arr" in this function.I
tried *using "sizeof" operator and realised it is not going to work
as "arr" will be *treated as pointer to an int!!!!!!*/
}
Thanks in advance
推荐答案
" prashna" < VA ****** @ rediffmail.com>在留言中写道
news：d4 ************************** @ posting.google.c om ...
| 1）为什么c允许额外的，，在数组intialiser？有没有
|这个优势？
|
|例如：int arr [5] = {1,2,3,4,5，};
| ^^编译器没有给出错误！
它使代码生成器更容易。
除此之外没有真正的好处...
| 2）如何确定作为
|传递的数组的大小函数的参数？
|例如：
| void foo（int arr []）
| {
| / *我想确定数组的大小arr在这个函数中。我
|试过*使用sizeof操作员并意识到它不会起作用
|作为arr将被视为指向int的指针!!!!!! * /
| } $ / $
数组的大小需要作为第二个参数传递。
C中没有其他方式（C ++允许你需要的东西，通过模板...）。
hth，
Ivan
-
http://ivan.vecerina.com
"prashna" <va******@rediffmail.com> wrote in message
news:d4**************************@posting.google.c om...
| 1)Why does c allows an extra "," in array intialiser?Is there any
| advantage of this?
|
| ex: int arr[5]={1,2,3,4,5,};
| ^^Compiler does not give error for this!
It makes things easier for code generators.
No real benefit besides that...
| 2)How to determine the size of the array which is passes as a
| parameter to the function?
| ex :
| void foo(int arr[])
| {
| /*I want determine the size of the array "arr" in this function.I
| tried *using "sizeof" operator and realised it is not going to work
| as "arr" will be *treated as pointer to an int!!!!!!*/
| }
The size of the array needs to be passed as a second parameter.
No other way in C (C++ allows what you need, through templates...).
hth,
Ivan
--
http://ivan.vecerina.com
prashna写道：
prashna wrote:
嗨大师的，
以下是我的问题...
1）为什么c允许额外的， "数组intialiser？这有什么优势吗？
ex：int arr [5] = {1,2,3,4,5，};
^^编译器没有给出错误！
2）如何确定作为函数的
参数传递的数组大小？
ex：
void foo（int arr []）
{
/ *我想确定数组的大小arr在这个函数中。我尝试*使用sizeof操作员，并意识到它不会工作
作为arr将被视为指向int的指针!!!!!! * /
}
Hi Guru''s,
Here are my questions...
1)Why does c allows an extra "," in array intialiser?Is there any
advantage of this?
ex: int arr[5]={1,2,3,4,5,};
^^Compiler does not give error for this!
2)How to determine the size of the array which is passes as a
parameter to the function?
ex :
void foo(int arr[])
{
/*I want determine the size of the array "arr" in this function.I
tried *using "sizeof" operator and realised it is not going to work
as "arr" will be *treated as pointer to an int!!!!!!*/
}
如果你想让foo知道大小，
然后你必须给foo更多信息。
void foo（int arr []，size_t n_elem）/ *元素数量* /
void foo（int arr []，size_t bytes）/ * size in bytes * /
-
pete
If you want foo to know the size,
then you have to give foo more information.
void foo(int arr[], size_t n_elem) /* number of elements */
void foo(int arr[], size_t bytes) /* size in bytes */
--
pete
在文章< d4 ************************** @ posting.google.com> ;，prashna写道：
In article <d4**************************@posting.google.com >, prashna wrote:
嗨大师'，
这是我的问题......
1）为什么c允许额外的， ;数组intialiser？这有什么优势吗？
ex：int arr [5] = {1,2,3,4,5，};
^^编译器没有给出错误！
它简化了生成C代码的代码。
哦，你的例子中不需要[5]中的5。
2）如何确定作为函数的
参数传递的数组的大小？
Hi Guru''s,
Here are my questions...
1)Why does c allows an extra "," in array intialiser?Is there any
advantage of this?
ex: int arr[5]={1,2,3,4,5,};
^^Compiler does not give error for this!
It simplifies code that generate C code.
Oh, and the 5 in [5] is not needed in your example.
2)How to determine the size of the array which is passes as a
parameter to the function?
[cut]
更改函数的接口，以便调用者也可以发送数组的长度（即添加一个额外的int参数）。
-
Andreas K？h？ri
[cut]
Change the interface of the function so that the caller also
sends the length of the array (i.e. add an extra int argument).
--
Andreas K?h?ri
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