My program has a nested  std::map object like  map &lt; int, set &lt; void *&gt; *&gt; m;   My program coredown in some situation, and I don't know the reason.  I suspect the problem is in  the nested map.   I only know using pmap to print simple map objects like std::map&lt;int, int&gt;, but don't know how to print more complicated map objects.  If a map is defined as map&lt; int, int &gt; m;, then  gdb pmap m int int    does work, but if a map is  defined as  map&lt; int, set &lt; void * &gt; * &gt; m;   then  gdb pmap m int set &lt; void *&gt; *   does not work
Supposing to have something like this:  #include &lt;map&gt; int main(){     std::map&lt;int,int&gt; m;     m[1] = 2;     m[2] = 4;     return 0; }   I would like to be able to inspect the contents of the map running the program from gdb. If I try using the subscript operator I get:    (gdb) p m[1] Attempt to take address of value not located in memory.   Using the find method does not yield better results:  (gdb) p m.find(1) Cannot evaluate function -- may be inlined   Is there a way to accomplish this?
How to encrypt individual folders? Let's say that I have a folder, within my Documents folder, that has files I want no one to access without a password.  Is there a way to lock down that folder so that it's password protected / encrypted?  In fact, is it possible to password-protect any individual folder? How do I get the size of a java.sql.ResultSet? Shouldn't this be a pretty straightforward operation? However, I see there's neither a size() nor length() method. Why do proof authors use natural language sentences to write proofs? I haven't read very many proofs. The majority of the ones that I've read, I've read in my first-year proofs textbook. Nevertheless, its first chapter expatiates on the proper use of English in mathematical proofs, so I suspect that most proof authors do use both English (or another natural language) and formal proof systems for writing their proofs. However, I can't imagine many circumstances where mathematical notation and a formal proof system wouldn't suffice to convey the author's pertinent thoughts.   I suspect that proof authors have good reasons for making use of both English and formal expressions in their proofs, but I can't think of what those reasons are. Why do proof authors use English and formal expressions to write proofs? Are there stylistic rules (or guidelines) that state how, and in what parts of the proof, an author should, and shouldn't, use English? Do I cast the result of malloc? In , someone suggested in a  that I should not cast the result of malloc. i.e., I should do this: int *sieve = malloc(sizeof(int) * length);  rather than: int *sieve = (int *) malloc(sizeof(int) * length);  Why would this be the case? MongoDB could not connect local server How do I avoid conversation with strangers while traveling? Suppose I know that I can find the $\gcd$ of two integers with the Euclidean algorithm. What is the 'extension' so I can use this method also for polynomials?  Edit: I found an easy answer with less rigor which is approachable without knowledge of matrices:    also the first 3 subchapters of Convert web page to image What happens if my ESTA expires on the day of arrival? I'm French and will travel the 14th of June to the US. My ESTA expires the 14th of  June 2013 and I'm wondering if my ESTA will be valid when I'll land in the US on the 14th of June 2013.  Does someone know anything about that? Down arrow button for choosing the desired site When searching for the desired SE site, the down arrow key (down) should work in order to choose the site one is looking for and hit enter to visit it, instead of using the mouse point to choose it. Would be pretty convenient. Draw ellipses with different coloring for their intersection in tikz? How do I color intersection of two ellipses in different color. For instances, the ellipses should themselves be colored as yellow and their intersection as red. My code for drawing ellipses is given below  \draw (-4,0) ellipse (8 and 3); \draw (8,0) ellipse (8 and 3);   UPDATE: In the comments to individual answers, I have requested to show it for three ellipses. A significant amount of zombies were detected in your city Can anyone please help and tell me if this sentence is correct?  &quot;A significant amount of zombies were detected in your city.&quot;  In my opinion it should be &quot;A significant amount of zombies was detected in your city.&quot; because &quot;amount&quot; should be in agreement with &quot;was&quot; even though amount usually refers to something plural. Are both (was and were) acceptable in this case? Edit1: Yes, &quot;number&quot; would be the correct one in this case. So allow me to ask one more thing.  &quot;A significant amount of purchases were detected...&quot;  Does the use of &quot;number&quot; apply in this case also? As purchase is not exactly a thing/person. And if no, is it correct to say &quot;A significant amount of purchases were detected...&quot;? Edit2: So, please tell me what is the correct phrasing?  &quot;A significant amount of purchases were detected...&quot; &quot;A significant amount of purchases was detected...&quot;  Or, since purchases are countable, is the use of &quot;number&quot; instead of &quot;amount&quot; correct here, as in:  &quot;A significant number of purchases were detected...&quot; &quot;A significant number of purchases was detected...&quot;  Or would amount be correct since a purchase involves money and it refers to the amount of money? Would greatly appreciate an answer, and if possible a detailed explanation. Minecraft Survival Mode Selecting the right crank length What is the best way to determine the correct crank length for my height and more specifically my leg length? When a word ends in 's' or 'x', do you add 's or just an '? 1) Alex's house      2) Alex' house     When the noun ends with the letter 's' or 'x', do I need to put 's' after an apostrophe or not?  I remember I read some rules related to this in my school grammar book, but now I've forgotten it. What happens if my order exceeds the bid or ask sizes? What will happen if my order exceeds the bid or ask size? For example, if the bid or ask is 100 shares, but I want to buy 100,000 shares, is it possible to do so? Is my ESTA valid for a second trip? Possibility of recovering files from a dd zero-filled hard disk I have "zero filled" (complete wiped) an external hard disk using dd, and from what I have heard: people said you should at least "zero fill" 3 times to be sure that the data are really wiped and no one can recover anything.  So I decided to scan the disk once again after I've zero filled the disk. I was expecting the disk to still have some random binary left. It turned out that it has only a few sequential bytes in the very beginning. This is probably the file structure type and other headers stuff. Other than that, it's all zeros and nothing else.  So if we have to recover any file from a zero filled disk, ...how? From what I've heard, even you zero fill the disk, you should still have some data left. ...or could dd really completely annihilate all data? Is there a system in place to prevent new users asking, answering and accepting answers to each others' off-topic questions? Normally new users are not allowed to up-vote until they gain a bit of reputation by receiving up-votes or accepts from the community of a site.  But this has a weak point that is being exploited:     A number of new users post, answer, and accept each others'    off-topic questions before we can close them (in less than 5 min).    Accepting each others' answers gains them enough reputation to    start up-vote each others' posts.   We are closing them and the moderators clean up afterwards but  this keeps happening over and over again and becoming frustrating  to the extent that I think a systematic solution might be required. Is there a system to prevent this kind of circumvention of  the reputation requirements using accepts by new users?  One possible solution might be to change the system so accepts from users who do not have enough reputation to up-vote  do not give any reputation (at least until the answer gets an up-vote). Missing $ inserted