Is it possible to find the length of an array if I have only the pointer to the first array element taking into account Array Decay? I'm creating an integer array whose input will be given by user, and I'm passing it to a function where it is decaying to a pointer(say int * a), now how can I obtain the length of the array in my function using only the available resource, that is the pointer to the first array element?  I have tried "templates"(template) which works on array and not on pointer. I did not want to use "struct"(putting array inside struct and passing the struct to function) as it just avoids the problem. I also did not want to stash the size in one block extra in the array as I did not want to consume more memory than what is required(even though it is a mere one). I also did not want iterators("begin" and "end"), they mostly do not work on pointers. I did not want a C++11 solution or a boost library solution too as I did not want to depend on version or a library.  #include &lt;iostream&gt; using namespace std; void func(int *a) {  //Now entire programming is to be done here as array has been passed  //How to find length using pointer a only, so that I can proceed with  //array operations?  //This function is not aware of length because of Array Decay but  //atleast has a starting point that is the pointer. } int main() { int array[5]={2,3,4,5,6}; func(array); //main()'s use is over now, control is shifted to void func(int *) return 0; }   I expect a method to find length using the pointer only, that is I expect the number 5(length of array) to get generated somehow inside func() method.
How to find the 'sizeof' (a pointer pointing to an array)? First off, here is some code:  int main()  {     int days[] = {1,2,3,4,5};     int *ptr = days;     printf("%u\n", sizeof(days));     printf("%u\n", sizeof(ptr));      return 0; }   Is there a way to find out the size of the array that ptr is pointing to (instead of just giving its size, which is four bytes on a 32-bit system)?
Windows 7 SP1 Windows Update stuck checking for updates I installed Windows 7 fresh and installed SP1. Now, when I try to check manually for Windows Updates it just hangs on the Checking for updates screen.    I tried running the tools in , but this did not fix the issue either:  No matter what I do it just hangs on the "Checking for updates..." screen and goes no further. How can I go back to the original interface layout? I don't know what the hell I did I just want to get back to modelling Can I use Bluray as a boot cd? Algorithm for computing Hadamard product of two rational generating functions If I have two generating functions $A(x) = \sum_na_nx^n$ and $B(x) = \sum_n b_nx^n$   then the Hadamard product is $(A \star B)(x) = \sum_{n} a_nb_nx^n$.  Now when $A$ and $B$ are both rational functions ($P(x)/Q(x)$ with polynomials $P, Q$) I've seen non-constructive proofs that $A \star B$ is also rational.  Given two rational generating functions $A$, $B$, is there an algorithm that efficiently computes $A \star B$? Or at least a constructive proof you could use to write an algorithm? For any smooth manifold, is it true that for any two points on the manifold, there exists a chart that covers the two points? In Windows XP we can search for files that contain a defined keyword (inside all files types).  Windows 7 can look inside files for a keyword, but only for text files. (*.doc, *.txt, *.inf, ...), not (*.conf, *.dat, *.*, ...).   don't contain any filter I can use for this.  How is this possible? javascript not working, working on fiddle but not on my webserver Some days ago I realized that  (as well as ) never throw an IOException when writing, flushing or closing.  Instead it sets an internal flag (trouble=true) when an error occurs. It's not possible to get the exact exception, but only if there was some exception ().  My question is: why would one want to have such behavior? Isn't that bad API design? I understand that information cannot be transmitted at a velocity greater than speed of light. I think of this in terms of the radio broadcast: the station sends out carrier frequencies $\omega_c$ but the actual content is carried in the modulated wave, the sidebands $\omega_c\pm\omega_m$. The modulation envelop has its group velocity and this is the speed at which information is being transmitted. We also know, for example, that x-rays in glass have a phase velocity which is greater than the speed of light in vacuum.   My question is, what exactly is it that is travelling faster than the speed of light?    EDIT: I know it couldn't be anything physical as its superluminal. My problem is, what is it that has absolutely no information content yet we associate a velocity with it. How to convert wstring into string? Is there a reason why the pin diagram of an RJ-45 looks like this?    I understand that the orange pair is used for Tx and the green pair for Rx. Why is it that the orange pair are kept together while the green pair are separated?  What are the consequences of messing around with this order as long as it is the same at both the ends? How to show that a Banach space $X$ is reflexive if and only if its dual $X'$ is reflexive? Why is a linear transformation called linear? Upgrade to the latest PHP version in ubuntu 16.04 I already read it from manual but I can't see difference..  su - change user ID or become superuser  sudo -s [command]   The -s (shell) option runs the shell specified by the SHELL environment variable if it is set or the shell as specified in passwd(5).  If a                    command is specified, it is passed to the shell for execution.  Otherwise, an interactive shell is executed.  sudo -i disappear description in manual Sqlite3 by default sorts only by ascii letters. I tried to look in google, but the only thing I found were informations about collations. Sqlite3 has only NOCASE, RTRIM and BIARY collations. How to add support for a specific locale? (I'm using it in Rails application) Run script as root at login (no sudoer user, shell session) Much like /etc/profile and ~/.profile but ran by root instead of the user is doing login. /etc/rc.local runs after boot but I need running the script before login. The user is not a sudoer one.   Thanks! Is there any way to recover unsaved notepad++ docs? I had to immediate shut down, and I lost about 20 unsaved tabs, is there any way to recover these? Applying Dupli-Objects Is it possible to bake dupliverts into one mesh for the BGE? (I have a large ground landscape that I use as the parent to duplicate trees, and the BGE doesn't support most modifiers.) Show that $x_{n+1}-\dfrac{x_n}{2}$ converges to zero implies that $(x_n)_n$ also converges to zero. Let $(x_n)_n$ be a sequence of real numbers such that $$\lim\limits_{n\rightarrow \infty}\left( x_{n+1} - \dfrac{x_n}{2}\right)=0.$$ Show that $(x_n)_n$ must also converge to zero.     $\textbf{My Attempt:}$   My original idea was to use the triangle inequality and the fact that $$\lim\limits_{n\rightarrow \infty}\left( x_{n+1} - \dfrac{x_n}{2}\right)=0$$   to show that the sequence $(x_n)_n$ is Cauchy and hence converges to some real number $a$, which would give me $$\lim\limits_{n\rightarrow \infty}x_n=a=\lim\limits_{n\rightarrow \infty}x_{n+1}\implies a-\dfrac a 2= \lim\limits_{n\rightarrow \infty}\left( x_{n+1} - \dfrac{x_n}{2}\right)=0\implies a=0.$$ However, I'm having trouble showing that $(x_n)_n$ is Cauchy.   Any suggestions/hints would be greatly appreciated. Thanks!