c - Pointers to structures, fields changing values inexplicably -

-

I am ready to complete that I am doing something stupid / wrong; This is what I expect.

I feel a feeling for the structures and the crop is coming from the fields to reach the fields. Follow the code.

Matrix. H: 

  #ifndef MATRIX_H_INCLUDED #define MATRIX_H_INCLUDED #include & lt; Stdlib.h & gt; Typefif structure {size_t size; Int * vector; } Vector_t; #endif // MATRIX_H_INCLUDED   
 main.c:  
  #include & lt; Stdio.h & gt; # Include & lt; Stdlib.h & gt; #include "Matrix." Vector_t * vector_new (size_t size) {int vector [size]; Vector_t v; V.size = Size; V.vector = vector; Return & amp; V } Int main (int argc, char * argv []) {vector_t * vec = vector_new (3); Printf ("v size is% d. \ N", vec-> size); Printf ("v is size% d. \ N", vec-> size); Return EXIT_SUCCESS; }   
 So this is a very simple program where I am creating a vector structure of size 3, return the pointer to the structure and print its size. This is the first print frequency at 3 which then changes to the next print at 2686668. What is happening?  
 Thanks in advance.   
 
 
 You are returning an indicator from the local variable  v  to  The vector_new  does not have a small chance to do this work till all the local variables are destroyed by the time of returning to  vector_new  and on  main  and Your pointer does not go anywhere. In addition, the memory  v.vector  is also a local array  vector . It also gets destroyed when  vector_new  returns.  
 This is the reason why you see garbage printed by your  printf .  
 Your code should be completely replaced with respect to memory management. The actual code should be allocated dynamically using the  malloc   vector_t  object can be dynamically allocated or in the  main  Can be declared as a local variable and it has been passed to  vector_new  to get started (depending on which method you want to follow depends on you).  
 For example, if we decide to do everything using dynamic allocation, then it can be of the following type  
  vector_t * vector_new (size_ size) ) {vector_t * v = malloc (sizeof * v); V- & gt; Size = size; v-> gt; Vector = malloc (v- & gt; size * size * v- & gt; vector); Return V; }   
 (And do not forget to check that  malloc  is successful).  
 However, we have been dynamically allocated, using  free  later. Therefore, you have to write a  vector_free  function for that purpose.

Comments

Post a Comment

Popular posts from this blog

php - PDO bindParam() fatal error -

-
I am trying to learn PDO, now I have written this small code, but it gives me a serious error: < P> Fatal error: Call a member function at a non-object dot () ... $ con = new mysqli ("127.0.0.1", "root", "", "csvdangercheck"); $ Query = $ con- & gt; ("Id,` var1`, `var2`) values ​​(" id,: var1,: var2) ";); $ query- & gt; bypass pattern (': id', $ id); $ query- & gt; BindParam (': var1', $ VAL1); $ Query- & gt; bindParam (': var2', $ val2); $ Query-> Executed (); I Trying to use print_r ($ con-> errorInfo ()) but Fatal error: Undefined method mysqli :: errorInfo ( ) ... can someone tell me what am I missing? Flaffeh said, you have PDO Missing Mysqy, try it: $ con = new PDO ('mysql: host = 127.0.0.1; dbname = csvdangercheck', 'root', '');
Read more

logging - How can I log both the Request.InputStream and Response.OutputStream traffic in my ASP.NET MVC3 Application for specific Actions? -

-
For a specific set of tasks, I need to log in to the incoming request inputstream as well as outgoing response. is. I am using an ActionFilterAttribute for this and overriding the OnActionExecuted and OnResultExecuted methods. So I'm starting with this idea ... Public category ActionLoggerAttribute: ActionFilterArrbit {Public Override Zero On-Offed Execution (ActionActioned Contact Filter Filter) {base.OnActionAxecuted (FilterContext); HttpRequestBase request = filterContext.HttpContext.Request; // TODO: Log the request. InputStream} Public Override Zero OnResultExecuted (ResultExecutedContext FilterContext) {base.OnResultExecuted (filterContext); HTTPRPSPointBase Response = FilterContacts Hpptex response; // TODO: Log on Response.OutputStream}} Ideally I'll hook it up with enterprise library logging because I'm already using it for error logging. Am I reaching the input and output stream at the right time? Can I easily use the Enterprise Library to log i
Read more

java - Why my included JSP file won't get processed correctly? -

-
I am trying to create Java web framework (and learning), and on the basis of 'Code Generator In the process of making the material view of the database in the process of development, I stumbled into a difficulty, which I do not know how to solve it. First of all, I want the following index.jsp : & lt; Body & gt; Use all pages to be created. & Lt;% @ include file = "header.jsp"% & gt; & Lt; Hours / & gt; & Lt;% @ included file = "body.jsp"%> & Lt; Hours / & gt; & Lt;% @ include file = "footer.jsp"% & gt; & Lt; / Body & gt; And, in body.jsp , I should have it like this: & lt; Jsp: include page = "$ {Application_modul}"%> Where application_modul is an attribute defined in its controller: request.setAttribute ("application_modul", "USER_ACCOUNT \\ ' View_user_account.jsp "); This file can be found properly, but the processed JSP does
Read more