in the below program for both class pointers pointing to null. Class contains normal function executing but class contains virtual function getting segmentation fault.
#include <cstdio>
using namespace std;
class A
{
[Code].....
[URL] ....
Which object's draw is being called?
Is:
char *endp = NULL;
the same thing as:
char *endp = 0;
?
In my raytracer-project I have the following function:
bool hitObjects(Ray &ray, std::vector<Object *> &objects, Vector3& normal, Material *mat) {
double tmin = K_HUGE_VALUE;
double t;
[Code]....
When I try to run this, I only get the message "Material pointer is null". So, somehow the pointer is null after the hitObjects-function is called, even though it isn't inside that function.
So I'm writing a small program for class, and for some reason I keep getting an error when trying to initialize head to NULL. Even threw in the namespace just to see, nothin'.
#ifndef NUMBERLIST_H
#define NUMBERLIST_H
using namespace std;
[Code].....
There's my header file. Not sure what I'm doing wrong with the constructor.
EDIT: Got it to work with nullptr, but still curious why that isn't working
In jumping into C++ it says something like this: It's not necessary but when you delete a pointer it's a good idea to reset it as a null pointer. That if your code try's to dereference the pointer after being freed, your program will crash. This happens to a lot of experienced programmers.
This could corrupt users data. delete p_int;
p_int = NULL;
1. If you can deference a pointer after the memory is freed, why can't you just delete the pointer?
2. If you can do 1, how do you delete the pointer using code?
3. Every thing I've read says that free memory is handed out in a sequenced order. I don't believe that is true at all. I may be wrong. Why can't you put the data in any number of places if it will fit. Isn't the compiler smart enough to know where bytes (bits)and pieces are stored?
4. If you storing anything in free memory must use a pointer to it?
5. Can a pointer or something similar be used with stack memory?
Here when NonlinearSolver called the constructor,
m_gradient() constructor is called to construct m_gradient, which in turns sets a variable called m_S to NULL(0), then in the assignment operator, because the m_S is NULL, Visual Studio throws an exception saying that destination pointer is null, but it's not fatal. I don't like that to happen because I have to press ignore many many times when the program is debugged, how can I fix this bug (not mine) to avoid the null destination pointer exception?
As an intermediate layer, the function calls boost unbounded array operator = which in turns calls std::copy which results in this error
Code:
NonlinearSolver(solver_type const & solver)
: m_gradient()
, m_function()
, m_projection() {
*this = solver;
[Code] .....
lets say I have a pointer p_unit of type c_unit* (c_unit is an a.b.c.)
I have a function that returns a pointer to a new c_unit object:
c_unit * man_add_unit() {
c_unit * local_p_unit;
unsigned short int local_run_code;
print_man_add_menu();
local_run_code = get_a_run_code(); // this bit just gets user input
switch (local_run_code)
[code]....
I assign that to p_unit, then add it to a vector v_units:
p_unit = man_add_unit();
v_units.push_back(p_unit);
cout << "New unit added.
";
The whole program runs on a loop, and another thing the user can do is to print out data on c_unit objects pointed to by v_units. The problem is, in that function up there ^ I give the user the option to go back to main menu without creating a unit.
Since "local_p_unit" is declared but not assigned an initial value, I'm guessing the function would return a "null" pointer (which is what's hanging me up). If I just let this run with the above code, and go to print out the unit data, the program crashes.
I tried to make an if thing with p_unit == 0 but this always returns false and doesn't catch the "bad" unit that will subsequently cause a crash.
Btw, I have considered assigning a reference to a generic c_unit object to that there local_p_unit so it won't return null, then remove pointers to that object from v_units at the end of the loop.. But I know there's got to be a better way.
struct mystruct{
int n;
};
class mscope{
public:
std::vector<mystruct> mv;
[Code] .....
So I have a vector of structs and I want to traverse it, find a struct that matches a constraint and obtain a pointer to that struct. I made a function for this purpose which takes a number and an empty pointer that will store the reference. However, after function returns the pointer becomes null. What could be causing this?
getting an invalid null pointer error message after a successful build. This program is supposed to ask for firstName, lastName, age and maJor and keep doing so until the age that is input is 0 and then the program closes. Here is what I have.
#include <iostream>
#include <string>
using namespace std;
[Code]....
VS 2012 / Windows 7 64 bit
class
class myclass {
public:
myclass(){/*stuff here*/}
myclass(int* p) {MyPointer = p; myclass()}
[Code] ....
it works until the myclass(int* p) calls myclass()
then the MyPointer will become CCCCCCCC (NULL value)!
is there a way to stop the second constructor from resetting the pointer value to null?
I am looking at one of the functions of an exercise:
void escape(char * s, char * t) {
int i, j;
i = j = 0;
while ( t[i] ) {
/* Translate the special character, if we have one */
switch( t[i] ) {
[code]...
Notice the while loop evaluates the current value in t to true or false. When we hit the null terminator, does that get evaluated as 0 and hence evaluates as a falsy value so the while loop exits?
I am trying to understand how to get the following value from a define. The code i am trying to understand is as follows:
Code:
#define RADIO_CONFIGURATION_DATA_RADIO_DELAY_CNT_AFTER_RESET {0xF000}
Code:
#define RADIO_CONFIGURATION_DATA {
Radio_Configuration_Data_Array,
RADIO_CONFIGURATION_DATA_CHANNEL_NUMBER,
RADIO_CONFIGURATION_DATA_RADIO_PACKET_LENGTH,
RADIO_CONFIGURATION_DATA_RADIO_STATE_AFTER_POWER_UP,
RADIO_CONFIGURATION_DATA_RADIO_DELAY_CNT_AFTER_RESET,
RADIO_CONFIGURATION_DATA_CUSTOM_PAYLOAD
}
and also have this
Code:
typedef struct {
U8 *Radio_ConfigurationArray;
U8 Radio_ChannelNumber;
U8 Radio_PacketLength;
U8 Radio_State_After_Power_Up;
U16 Radio_Delay_Cnt_After_Reset;
U8 Radio_CustomPayload[RADIO_MAX_PACKET_LENGTH];
}
tRadioConfiguration;
so then in the api i have the following
Code:
for (; wDelay < pRadioConfiguration->Radio_Delay_Cnt_After_Reset; wDelay++); .
so my question is how do i declare my variables, correct terminology ?, to achieve this.
I have 22 CButtons and I'm trying to set each one to the corresponding position in a CButton array of size 22 in the constructor.
Code:
*buttons[0] = m_button1;
This code gives me an error in the compiler.
error C2248: 'CObject:perator =' : cannot access private member declared in class 'CObject'
Cam is a pointer to a structure and viewpoint is a vector located within the struct. I am trying to read in from a file the coordinates for the vector. I have also tried &cam->view_point->x as well as &cam.view_point.x and it tells me that I am requesting something not in a struct
Code: count= fscanf(in,"%d %d %d", &cam->view_point.x, &cam->view_point.y,&cam->view_point.z);
In C++, how do i call a method member of class A from a class B, using a pointer. By the way Class A and B are of different types.
I read that when a pointer is pointing to member function it can only point member functions within the class. But how can i point to a member function outside the class.?????
for example
class A {
public:
int add(int x) {
return x+x;
[Code] .....
When you login to my site my loginservice which is done by ajax and json make a session called context.Session["Name"]. With BreakPoints it shows that everything is good and the variables are in place. However when I use Session["Name"] it comes out as null.
I will add my code at the bottem not
using System;
using System.Collections.Generic;
using System.Linq;
[Code].....
Why this makefile only executes the first entry, compiling only the first program listed?
###########################################################
#
# Simple Makefile for Operating Systems Project 2
#
###########################################################
vowcon:
g++ -o vowcon vowcon.cpp -pthread
osproj2c:
g++ -o osproj2c osproj2c.cpp -pthread
osproj2b:
g++ -o osproj2b osproj2b.cpp -pthread
osproj2a:
gcc -o osproj2a osproj2a.c -pthread
clean:
rm osproj2a osproj2b osproj2c osproj2d vowcon
how I can run this as a separate process from the parent program, like a child process,
and return the result back to the parent program.
this script is as follows.
if file "/Stuff/s" exists then continue to run, if file "/Stuff/t" exists, then print "started" if file "/Stuff/t" does not exists, then print "stopped"
if file "/Stuff/s" does not exist then print "quit" and then quit.
Code:
void controlxmmscheck( ) {
if( access( "/Stuff/s", F_OK ) != -1 ) {
xmmscheck
} else {
[Code]....
I have this problem for an assignment, and one of the functions that I created for it is nothing fancy; just a function that'll take in a number and error-check to make sure the input is valid. However, after doing it, when the program calls that function, it skips the cin statement and ends the program, without letting the user input his number. The function in question is called getSubLength.
Code:
#include <iostream>
#include <string>
#include <iomanip>
#include <cstdlib>
using namespace std;
const string JANUARY = "January";
[code]...
We have been assigned to create a program that uses multiple functions. The professor has given us code for two of the functions, one to open a file and then another one to read the files contents and output them. I have put these into my program but they will not execute. The program does run, but the functions themselves are not executing. I have practiced with other functions that contain no parameters and those run fine, but the functions she gave us have multiple parameters.
The code I have so far is below:
#include <iostream>
#include <iomanip>
#include <fstream>
#include <string>
void PrintFile (string FileName, ifstream& inFile);
int main () {
ifstream inFile;
string fileName;
[Code] .....
I tried.
cin.get();
and
return 0;
is there a better way to keep the user info displaying without closing the console window.
PHP Code:
using namespace System;
ref class A {
public:
A(){Console::WriteLine(L"A constructor");}
virtual void func(){foo();}
void foo()
[Code] .....
Supposing that class A is the development code; and so for unit-testing purpose I create a mock for it. But I don't know how to override A's constructor such that it will not get executed in my unit-test code.
I am currently working on a c++ project that will input students and process their grades. I encountered a problem and my code stops executing after the getScores function. Im not sure what the problem is, but im guessing its something within the function and the loops.
//Name: getScores
//Description: Will get scores for student
//Parameters: None
//Return: testScore
double getScores()
[code]....
I need to make a program which can play a audio file as background while executing other operations .
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