oop - Why C++ new is not returning pointer to the object it creates? -

-

I understood the following code, according to my knowledge when I declare new use of something new, then this particular Creates an object of type and gives the indicator on that object. But here when I use a new student object, it does not return pointer to the object. Also, when I do not make any type of conversion from student to student, instead of giving an error, new student (s1) " student (student *) " Call me P> 

  #include & lt; bits / stdc ++ H & gt; using namespace std; Class student {public: cool; Student (student * s) {// is taking it for constructor indicator, while I am calling it under this value - & gt; Cool = s-> Quiet; } Student () {it-> Calm = 1; }}; Zero blah (student) {printf ("cold:% d \ n", S. col); } Int main () {student s1 = new student (); // New student is not returning here * s1.cool = 2; Student S2 = New Student (S1); // Here we are passing S1, which type of students are, but why is the producer (student *) called ??? Blah (s2); }   
 The following output is that I am without any error:  
 
 Good: 2    
  
  Students (student * s) 
 
 You are leaking memory.  
 / code>  
 The conversion is used to fully satisfy, because this is not  explicit  marked here: What happens here:  
  student s1 = new student ();   
 Do you pull a new  student  object? The expression  new  expression evaluates an indicator when the compiler sees the assignment, then it recognizes that the assignment will not work because  s1  a  student  And you are assigning a  student *  to do this so it looks around to change it and I look for the constructor mentioned above.  
 So what you are doing is equivalent:  
  student s1 = student (new student ());   
 Since you do not always mark  delete , the heap allocation is leaked, but otherwise your program works properly from your perspective.  
 If you mark the conversion constructor in this way:  
  Clear student (student * s)   
 Then compiler this The creator will not use it automatically for conversions, it is necessary to specify some kind of sound, and line  student s1 = new student (); In reality, there will be a compile time error, while allowing the student to s1 = student (new student ());  to work (but of course it would still be the cause of a memory leak).

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: 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

php - How can I cram 6+31 numeric characters into 22 alphanumeric characters? -

-
I have a 6 digit number and a 31-digit number (such as "234536" and "201103231043330478311223582826") that I The API needs to be crawled in the same 22-character alphanumeric field that uses PHP. I tried to convert each one to 32 (using custom code could not handle the base_convert () large number) and to connect with a single-character delimiter, but It only gives me 26 characters This is a restore API, so the letters should be URI-protected. I would like to do a database table cross with two references without reference to another reference value, if possible, any suggestions? Instead use a radix of 62. This will give you 22 characters for the top, 3.35 for the pre and 17.3 for the next. & gt; & Gt; & Gt; Math.log (10 ** 6) /math.log (62) 3.3474826039165504 & gt; & Gt; & Gt; Math.log (10 ** 31) /math.log (62) 17.295326786902177
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