If I have the following function in C++:
void functionName(HANDLE arr[100])
{
}
HANDLE hHandles[100];
functionName(hHandles);
Is there any way to know the size of 'arr' inside the functionName? (Without hardcoding it there)
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1Not without passing it in as an arg, no. That is why std containers store the array size.crush– crush2012-02-16 18:28:44 +00:00Commented Feb 16, 2012 at 18:28
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related FAQfredoverflow– fredoverflow2012-02-16 18:30:18 +00:00Commented Feb 16, 2012 at 18:30
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@crush: if you change the function parameters it can be done.Mooing Duck– Mooing Duck2012-02-16 18:51:26 +00:00Commented Feb 16, 2012 at 18:51
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possible duplicate of determine size of array if passed to functionBo Persson– Bo Persson2012-02-16 21:37:11 +00:00Commented Feb 16, 2012 at 21:37
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4 Answers
Use template to catch the N in T[N]
template <size_t N>
void function(HANDLE (&arr)[N])
{
std::cout << N << " is here\n";
}
2 Comments
ahmd0
OK, yeah, this one uses templates though.
Joel Falcou
you dont have many options anyway. The fact the size of an array is part of the array type in C++ is a very strong informations. Not using it result in subpar solution.
No. Unless you have put a delimiter at the end yourself before passing. In case of strings (which are character arrays)the delimiter is the null character '\0' so the size can be checked. But normally for arrays this can't be done.
1 Comment
Mooing Duck
Terminator is a good suggestion, but there's several ways to do this.
Consider sending the size as a separate parameter instead.
void functionName(HANDLE arr[100], size_t size)
{
}
answered Feb 16, 2012 at 18:37
Muhammad Hewedy
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1 Comment
Cheers and hth. - Alf
Consider instead using
std::vector.You could also use a global variable or a class attribute.
size_t size = 100;
void functionName(HANDLE* arr)
{
//size will be visible here and in any other
// functions and you can change its value during run-time
}
