I am confused between : returning an object (but then the object is copied from the local variable in the function, which consumes memory) returning a pointer (but then you have to remember to delete it, in the calling code, which is weird) returning a reference (but this is not possible because this would be a reference to a local var...
I am having a pointer *ip_address_server which holds the ip address of the server : in_addr * address = (in_addr * )record->h_addr; char *ip_address_server = inet_ntoa(* address); Clearly, when I use printf to print the value of it, it gets nicely printed. printf("p address %s" , ip_address_server); But now if I declare...
I'm making a TextField class, which at the moment stores a reference to a variable, and whenever the programmer wants, they can call TextField.show() and the referenced variable will be read and displayed on-screen. This however can result in problems if the reference becomes invalid. For example, if the variable referenced goes out of ...
Possible Duplicate: Is array name a pointer in C? Are arrays and pointers implemented differently? I have come across this question because , in both the cases we access elements from the starting address of an element.So , there should be close relation between them . Please explain the exact relation between them . Thanks. ...
For example: void DeleteLastNode(NodeType **L) If **L represents the address of the variable L, can it not be replaced by &L instead? Also, if I were to use *L or simply just L, would I not be able to change L's contents? If so, what's the difference of using *L and L, if L is a pointer to it anyways? Would I not be able to look at it...
I've got a method that creates some Foo and adds it to a vector of Foos. Foos are in charge of deleting their Bars during destruction. The Foo constructor takes a pointer of Bars and a size of them. When the function returns, the local Foo gets deleted and destroys its Bars, however I get a valid Foo object back. How should I be handlin...
I am reading strings in C++ using fread where I am reading and storing shortSiteText in siteNames_. siteNames_ is declared as std::vector<char*> siteNames_; I use siteNames_ in other functions but because shortSiteText is a pointer, when I call the delete command on it, the last entry in siteNames_ is changed. How do I prevent this? fo...
I need to write a simple program that ask the user to insert 4 double type variable in a struct variable data. struct Data { double a; double b; double c; double average; }; struct Data *ptr_name; int i; First, ask user the size: printf("Please enter the size:"); scanf("%d", &size); Then, use ...
I've this assignment to implement strcmp function. Sometimes it runs okay but other times it crashes. Please help me. #include <iostream> using namespace std; int mystrcmp(const char *s1, const char *s2); int main() { cout<<mystrcmp("A","A")<<endl; cout<<mystrcmp("B","A")<<endl; cout<<mystrcmp("A","B")<<endl; cout...
Right now I have a pointer set to a row in my 2D array. I want that pointer to stop pointing to that row, but I will be using the pointer later for something else. I just want to know how to unset the pointer after it is initialized and has pointed to a row. double* tempRow; tempRow = (double*) malloc(size * sizeof(double)); ... te...
Hi all, I'm facing a problem initializing an array with pointers to members of a structure. The structure members have to be accessed through a structure pointer. The reason for this is we initialize the pointer at runtime to a memory mapped address location. The following code snippet is an example of the problem; #include <stdio.h> ...
i have two classes namely Flight and Runway. Now i am trying to pass an array of these objects as parameter to a function. void fun(Flight ptr1[],Runway ptr2[]) { ... ... } ptr1 should point to an array of Flight objects and ptr2 should point to an array of Runway objects. Now inside this function fun() how do i access members of the...
Hello everyone! I've programmed for a while in Java and .Net, but never really used C or Objective C. I'm still trying to understand a few concepts. I was working on a simple program just to see how I can make an array of structures. Which I believe I got right. I'm having a hard time figuring out how to access the subclasses and store ...
Hi, I am trying to overload the = operator on a simple C++ class called Set that contains a dynamic array of ints. For the = operator, I first want to check for self assignment, so I wanted to compare 2 pointers to make see if they have the same memory address. Here's the code: Set& Set::operator=(const Set& setEqual) { //first check fo...
are pointers of integer or unsigned datatype? ...
When you create some pointers inside the scope of a function, what happens when the function goes out of scope? Do they get destroyed or should I call delete on them at some point? void XMLDocument::AddNode(XMLNode& node) { std::string val = node.GetNodeName(); TiXmlElement* el = new TiXmlElement(val.c_str()); // What about th...
hi everybody, i can't understand following defining pointer variable. can you help me? double(*)(double *) foo; note : sory, i edit name of variable func to foo. ...
Hi! let's say i want to have a member variable for a pointer to std::vector but i do not want to specify what type of variable it stores. I want to access only those functions that are independant of it's actual generic type. is this possible with c++? something like this: class Foo{ public: void setVec(std::vector* someVec){ ...
Hi all, Wonder if anyone can clear up the following for me. What happens if I point a pointer to another pointer ? E.g Pointer 1 = Object Pointer 2 = Pointer 1 What if I then change pointer 1 : Pointer 1 = Object 2 Where does pointer 2 now point ? Thanks, Martin ...
Hello. I have a question regarding the speed of pointer dereferencing. I have a structure like so: typedef struct _TD_RECT TD_RECT; struct _TD_RECT { double left; double top; double right; double bottom; }; My question is, which of these would be faster and why? CASE 1: TD_RECT *pRect; ... for(i = 0; i < m; i++) { if(p[...