The following code just keeps on crashing when it reaches the part with _itoa, I've tried to implement that function instead and then it got even weirder, it just kept on crashing when I ran it without the debugger but worked fine while working with the debugger.  # include "HNum.h" # include &lt;stdio.h&gt; # include &lt;stdlib.h&gt; # include &lt;string.h&gt; # include &lt;assert.h&gt; # define  START_value 30   typedef enum {     HNUM_OUT_OF_MEMORY = -1,     HNUM_SUCCESS = 0, } HNumRetVal;  typedef struct _HNum{     size_t Size_Memory;      char* String; }HNum;  HNum *HNum_alloc(){     HNum* first = (HNum*)malloc(sizeof(HNum));     if(first==NULL){         return NULL;     }     first-&gt;String =(char*)malloc(sizeof(START_value));     if(first-&gt;String==NULL){         return NULL;     }     first-&gt;Size_Memory = START_value; // slash zero &amp;&amp; and starting from zero index;     return first; }  HNumRetVal HNum_setFromInt(HNum *hnum, int nn){     itoa(nn,hnum-&gt;String,10); }  void main(){     HNum * nadav ;     int h = 13428637;     nadav = HNum_alloc();     nadav-&gt;String="1237823423423434";     HNum_setFromInt(nadav,h);     printf("nadav string : %s \n ",nadav-&gt;String);     //printf("w string %s\n",w-&gt;String);     //printf("nadav string %s\n",nadav-&gt;String);     HNum_free(nadav);  }   I've been trying to figure this out for hours and couldn't come up with anything... The IDE I'm using is Visual Studio 2012 express, the crash shows the following: "PROJECT C.exe has stopped working windows can check online for a solution to the program."
The following code receives seg fault on line 2:  char *str = "string"; str[0] = 'z';  // could be also written as *str = 'z' printf("%s\n", str);   While this works perfectly well:  char str[] = "string"; str[0] = 'z'; printf("%s\n", str);   Tested with MSVC and GCC.
How to to calculate the hash of an unordered set Suppose I have a set of elements, with known hash (e.g. SHA-2). How can I calculate the hash of the set? With it I mean an unordered set, so the order of elements is undefined and shall not play any role in determining the hash of the set.  In theory any commutative operation applied to the hashes should be fine, but I have the strong feeling that XORing all of them together is quite unsafe. An attacker could add an element to the set to produce a hash collision, although finding an element with that wanted hash is as hard as breaking the hash of the whole set.  Anything better solution than the trivial one of sorting the elements into a list, calculating their hashes and then calculating the hash of the hash list?  I think Merkle trees can't help here if they are based on some sort of ordering of the elements. I'd like to be able to decompose a concave mesh into a set of convex meshes for 2 reasons:   Transparent rendering Physics shapes   Is there an algorithm that takes a set of triangles (concave) as input and outputs a number of sets of triangles (convex)?  I'd like it to not fill in the holes between parts of the original mesh.  I've already come across a small idea: find all the concave edges, and split the meshes along the edge loops.  Am I on the right track?  How could I implement this? What is the importance of eigenvalues/eigenvectors? Is trace of regular representation in Lie group a delta function? My major is physics. I need to use some tools in group theory, but I am really  confused by the trace in compact infinite groups. The following is my question:  In discrete group theory, the irreducible representation of identity group element $e$ is always an identity matrix. So the trace of $e$ under  regular representation is the order of the group : $\chi(e) = |G|$. I hope to get  similar result for Lie group. For example, SO(2) has infinite number of irreducible representations, $D^{(m)}$, where $m=0,\pm 1, \pm 2,\cdots $. All of them are 1-dimensional $D^{(m)} = e^{im\phi}$. Here $\phi$ is the rotation angle. For element $R(\phi)$ in SO(2), the trace in $m$th irreducible representation should be  $\chi(R(\phi))=e^{im\phi}$, if we sum all these traces up, we get the trace in regular representation. So what is the trace of $e$ in the regular representation ? It seems to be infinite. Good abstract algebra books for self study Last semester I picked up an algebra course at my university, which unfortunately was scheduled during my exams of my major (I'm a computer science major). So I had to self study the material, however, the self written syllabus was not self study friendly (good syllabus overall though).  The course was split up into 3 parts, group theory, ring theory and field theory. As a computer science major we only had to study the first 2.  Now that I passed the exam for this course I want to study the field theory part ( which covers Galois theory, etc).  So, now I want to ask whether any of you know any good books on abstract algebra, which lift off at basic ring theory and continue to more advanced ring theory and to finite fields, Galois theory, ...  Please keep in mind that I am not a math major, and that I would like books which are suited for self study (thus a lot of examples and intuition).  Thanks in advance! How can I identify an anonymous inner class in a NotSerializableException How specific does "beast you have seen" have to be for Wild Shape? Starting at 2nd level, you can use your action to magically assume the   shape of a beast that you have seen before.   This doesn't say anything about the gender or age of the beast, so can a druid change into a female bear if he has only seen male bears? Can he change into a bear cub if he has only seen adult bears? What about hens/roosters/chickens, which look quite a bit different? Or does the gender of the animal shape just match the gender of druid? Possible Duplicate:          I was wondering if there's any good reason to still use blob fields in a database. A couple of years ago I worked with a DB with a bunch of images in it, the DB was very slow and I couldn't see any good reason to keep the images inside the DB, so I got the images out and stored the filenames instead.  Was this a smart move? What would you do in my place? Integral representation $B_T^3$ I have to find a $F_t$ such that $B_T^3=E[B_T^3]+\int_0^T F_t dB_t$. I have shown by ito formula that $B_T^3=\int_0^T 3 B_s^2 dB_s+\int_0^T 3 B_s ds$. Could you please help me? I thought the new Apple font was called San Francisco, but I cannot find it in the font list of the Keynote.app for my Mac. Is it called another way or it is not available for Keynote?  I am currently using OS X El Capitan. Past Subjunctive vs Future Subjunctive form In Adobe Photoshop I am able to select multiple layers at once with Shift+Click.  How can I do that in GIMP? Creating a byte array from a stream What is the prefered method for creating a byte array from an input stream?   Here is my current solution with .NET 3.5.   Stream s; byte[] b;  using (BinaryReader br = new BinaryReader(s)) {     b = br.ReadBytes((int)s.Length); }   Is it still a better idea to read and write chunks of the stream? I have been reading Hamilton Chapter 13 and he has the following state space representation for an ARMA(p,q). Let $r = \max(p,q+1)$.Then the ARMA (p,q) process is as follows: $$ \begin{aligned}  y_t -\mu &amp;= \phi_1(y_{t-1} -\mu) + \phi_2(y_{t-2} -\mu) + ... + \phi_3(y_{t-3} -\mu) \\ &amp;+ \epsilon_t + \theta_1\epsilon_{t-1} + ... + \theta_{r-1}\epsilon_{t-r+1}.  \end{aligned} $$ Then, he defines the State Equation as follows:   $$  \xi_{t+1} = \begin{bmatrix}      \phi_1 &amp; \phi_2 &amp; \dots &amp; \phi_{r-1} &amp; \phi_r \\      1 &amp; 0  &amp; \dots &amp; 0 &amp; 0  \\      \vdots &amp; \vdots &amp; \dots &amp; 0 &amp; 0 \\      0 &amp; 0 &amp; \dots &amp;1 &amp;0 \end{bmatrix} \xi_t  +  \begin{bmatrix}      \epsilon_{t+1} \\     0\\\vdots  \\     0       \end{bmatrix}  $$  and the observation equation as:  $$y_t = \mu + \begin{bmatrix}      1 &amp; \theta_1 &amp; \theta_2 &amp; \dots &amp; \theta_{r-1} \\     \end{bmatrix} \xi_t. $$  I do not understand what the $\xi_t$ is in this case. Because in his AR(p) representation it is $\begin{bmatrix}      y_{t} - \mu \\     y_{t-1} - \mu\\\vdots  \\     y_{t-p+1} - \mu       \end{bmatrix}  $ and in his MA (1) representation it is $\begin{bmatrix}      \epsilon_{t} \\     \epsilon_{t-1}      \end{bmatrix}  $.  Could someone explain this to me a little bit better? How is arccos derived? Stupid question but I need to understand:  If $ \cos = \dfrac{\text{adjacent}}{\text{hypotenuse}} $  What is arcosine? $ \text{adjacent} \cdot \text{hypotenuse}$? Is this the same for arcsine and arctangent? Show rigorously that the sum of integrals of $f$ and of its inverse is $bf(b)-af(a)$ How can one show that a möbius transformation maps the unit circle to some axis? Suppose I have the möbius transformation f(z) = $\frac{1+z}{1-z}$ and I want to show that it will map the unit circle (excluding the point 1) to the imaginary axis.  Would it help to express my unit circle in polar form?     Here's what I did: f(e$^{i\theta}$) = $\frac{1+e^{i\theta}}{1-e^{i\theta}}$  But I'm not sure where to go from this step. I was writing test classes for my apex Rest Service that I had built for an Ipad app.  I noted some very interesting things while experimenting. Before doing anything, I just did a google search and found an interesting blog post by Jeff.    @RestResource(urlMapping='/v.9/member/*/results/*')  global with sharing class MemberRestSvc {  @HttpGet  global static ReturnClass doGet() {  String[] uriKeys = RestContext.request.requestURI.split('/'); // get the member name from the uri String memberName = uriKeys.get(uriKeys.size()-3);  // do awesome programming stuff here &amp; catch any exceptions try {    List&lt;Contact&gt; contacts = [Select Id From Contact where member_name__c = :memberName];   return new ReturnClass('true', 'Query executed successfully.', contacts);  } catch (Exception e) {   return new ReturnClass('false', e.getMessage(), null); }   }   global class ReturnClass {  global String success; global String message; global List&lt;Contact&gt; records;    global ReturnClass(String success, String message, List&lt;Contact&gt; records) {   this.success = success;   this.message = message;   this.records = records;  }  }  }   And here is the test class  @isTest private class Test_MemberRestSvc {  static { // setup test data   }  static testMethod void testDoGet() {  RestRequest req = new RestRequest();  RestResponse res = new RestResponse();  req.requestURI = 'https://cs9.salesforce.com/services/apexrest/v.9/member/me/results/today';   req.httpMethod = 'GET'; RestContext.request = req; RestContext.response = res;  MemberRestSvc.ReturnClass results = MemberRestSvc.doGet();  System.assertEquals('true', results.success); System.assertEquals(10, results.records.size()); System.assertEquals('Query executed successfully.', results.message);  }  }   I just commented a few lines and ran and it. I still achieved enough test coverage so my question is why do I need to simply instantiate the Rest request and response objects since I am directly calling the class?    @isTest   private class Test_MemberRestSvc {    static {     // setup test data     }  static testMethod void testDoGet() {  /*RestRequest req = new RestRequest();  RestResponse res = new RestResponse();  req.requestURI =    'https://cs9.salesforce.com/services/apexrest/v.9/member/me/results/today';   req.httpMethod = 'GET'; RestContext.request = req; RestContext.response = res; */Commented the code meant for REST apex intialization and merely calling the method!!  MemberRestSvc.ReturnClass results = MemberRestSvc.doGet();  System.assertEquals('true', results.success); System.assertEquals(10, results.records.size()); System.assertEquals('Query executed successfully.', results.message);  }  }   Can someone explain this behavior? Also what are the best practices for writing Test classes for apex Rest services? Find an example of a function sum $\sum_{n=1}^\infty u_n $ that converges   uniformly on $[a,b]$ and converges absolutely pointwise, but   $\sum_{n=1}^\infty |u_n| $ doesn't converge uniformly on $[a,b]$.   This seems pretty straightfoawrd but it's really hard to find an example. The choice of $u_n$ must be very specific. You can actually prove any power series wont work (due to Abel's theorem)  In addition, in order to prove the uniform convergence, $u_n$ must not satisfy Weierstrass' M-Test (because then $\sum |u_n|$ would converge uniformly aswell) Is there a such thing as an exchange program in Harry Potter? In the Harry Potter universe, is there any mention of an exchange student at Hogwarts or one of the Hogwarts students going on exchange at another school?  This happens all the time in the "muggle" school systems I'm sure it would happen in the wizarding schools as well.