I am checking to see if two references are bound to the same object. My instincts tell Me, "Check their addresses. If they match, they are bound to the same." At the same time, I have not found anything in the C++ standard which would support this approach. Am I missing something? Is there wording which backs up My instincts? Is there a standard function to do this?
View 4 RepliesThis has been bothering me for a while now, and I finally put together an example:
#include <iostream>
#include <string>
using namespace::std;
[Code]....
In the code above, the two classes hold pointers to each other, and that's fine but it doesn't seem right since C++ prefers to pass by reference. Yes, it can still do that (see testbox and testball) but even that seems odd to me because still you need to use pointer notation for the enclosed object. Am I the only one who feels this way, and should I just get over it? Or am I missing something that would allow an object to hold a reference?
I'm working on collision detection for a game in SFML. I successfully designed a Spatial Partition grid to speed up the collision test, in the following of this tutorial: [URL] ....
But now I have an issue with one aspect of it: Going through a vector of objects and testing all the OTHER objects in the vector against said object. The author puts it into psueudocode here:
For each tick of the clock
For every object in the game
Get all the other objects in the same grid square
For each other object in the same grid square
I have trouble with the last line, because in iterating through a vector I am not sure how to skip over the current object. Here is my own code (a couple of sysntax errors but this is a c++ question not an SFML question):
//for every moveable object
for(int i = 0; i < rects_.size(); i++){
std::vector<sf::RectangleShape> posibleObjects_; //this will be a vector of WorldObjects in a real game
//for every object in that object's gridsquare
for(int j = 0; j < rects_.size(); j++){
if(rects_[i].intersects(rects_[j])){
//collision
} } }
The problem is, a collision will always be reported because somewhere in the vector the object will eventually check against itself which is always a true collision. What is the correct way to do this?
What rvalue references are? How are they useful? What are temporary objects?
View 1 Replies View RelatedI have a situation where I have two identical storage containers:
Code:
////////////// multiplatform version
union _SOVector3 {
struct { float x, y, z; };
struct { float r, g, b; };
float v[3];
[Code] .....
SOVector3 is part of a namespace with specialized functions that are generic and intended for multiplatform usage.
GLKVector3 is dedicated to the Mac and has its own set of functions.
But what I want to do is freely interchange the storage between these two namespaces. Such as like this:
Code:
start = clock();
SOVector4 myVec4 = SOVector4Make(1.0f, 3.0, 6.0f, 1.0);
SOMatrix4 myMat4 = SOMatrix4Identity;
for (uint i=0; i<100000; ++i ) {
[Code] ....
But I am getting errors when I typecast this.
The question is to write a recursive boolean function that compares two stacks and returns true if they are identical. This is where I get stuck:
If the top items of both stacks are the same, the recursive call always returns true, because 'true' is saved on top of the return stack.
Here is my code:
template<class Type>
bool identicals(stackType<Type> s1, stackType<Type> s2) {
if(!s1.isEmptyStack() && !s2.isEmptyStack()) {
if(s1.top() != s2.top())
[Code] ....
Say I have something lke
Code:
#define FOO BAR
#if FOO == BAR
doX();
#else
doY();
#endif
This causes doX(); to be executed. But the intent is to have doY(); be run. I'm guessing this is because BAR is undefined and therefore blank, so blank equals blank. Is there some way to compare the symbol FOO was set to instead of its value, BAR?
In the below program, when we have 4 consecutive spaces, the following comparison will not be equal: (x / tabstop != (x + spaces) / tabstop). If we have, let's say, only 2 consecutive spaces, then the comparison will be equal. So we know to print a tab with 4 consecutive spaces and not print a tab otherwise. How do we know this kind of division comparison would work in every case?
#include <stdio.h>
#define TABSTOP 4
int main(void) {
size_t spaces = 0;
int ch;
size_t x = 0; /* position in the line */
size_t tabstop = TABSTOP; /* get this from the command-line
[Code] .....
I developed this simple sample program to test cos():
Code:
#include <cmath>
#include <iostream>
using namespace std;
int main() {
const float radiansToDegrees = 180.0f / 3.141592653589793f;
float c = sqrt(2.0f);
float a = 1;
float angleRadians = cos(a/c);
float angle = radiansToDegrees*angleRadians;
}
I expected angle to be 45 exactly, but it's value is: angle = 43.558804
Why is the angle not 45 degrees? What did I do wrong?
I have a text file with state names, and state abbreviations, thusly:
ALASKA
AK
ARKANSAS
AR
..and so on.
I have to load the abbreviations ONLY from the file into an array of char[ - (already done and tested).
I have to get a 2 char abbreviation as a string,then test it against the state array to make sure it is a valid abbreviation. As it stands, my test is never finding an invalid abbreviation..
Here is where I get the input:
void getState() {
char state[10];
getString("Please enter the state as a 2 char abbreviation:",state,10);
printf("State Entered:%s", state);
validState(state);
[Code] ....
I was wondering what function was the C++ equivalent for testing to see if a user input is numeric.
I have equivalents in Ruby, Java, Python, VB, VBA, php, but being a novice in C++, I have yet to find one - even with Google.
And I know C++ is such a wonderful language, that its extensive library must have one somewhere - considering it's already 2013!
I am testing HTTP Headers and I have an strange problem. When I get the response of the server, it is the correct one the first time. If I use a for loop to send more than one request and get more than one response, this response seems to be overlapped with the previous ones. To a better explanation of the problem I attach the code I am using and the output generated:
TCPSocket.h
-----------
#ifndef _TCPSOCKET_H_
#define _TCPSOCKET_H_
class TCPSocket {
private:
int localSocket;
[Code] .....
So, a bigger loop, a bigger the response of the server. However, I know the response of the server is always the same.
I know I can use ping internally to test a device's connectivity. What can I use to test devices on another network (assuming ports are forwarded, and their IP addresses are at my disposal)? I was looking into the TCP Client class.. would that also work with devices using DynDNS?
View 7 Replies View RelatedWhat I have: A basic program for infinitely looping after and testing for an active process. It has a delay system built in to make it so it is not constantly iterating.
What I need: A way to get process IDs from other Processes other than my program. With a way to use that ID to detect if that process is active on the computer or not.
Parts of my code that need changing:
/* Code for handling the process would go here */
/* Code for detecting the target would go here */
What the goal of my program is: Perform operations to terminate the process of cmd.exe when it is active on the user's computer. Then output the status of the process and the time it took to find that process to the user.
It contained functions that I needed, but I need more information on how to apply them to other processes instead of the parent of my program and its' children.
Here is the code I prewrote for this so far:
Code:
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define ZERO 0
#define INFINITE 1000000000000000
[Code] .....
I have to make program which can generate a lot of random numbers and than prepare histogram with each number. Histogram must look that:
0 ( 50):*****************************************
1 ( 59):********************************************** ***
2 ( 42):***********************************
3 ( 49):****************************************
4 ( 41):**********************************
5 ( 53):********************************************
6 ( 60):********************************************** ****
7 ( 47):***************************************
8 ( 54):*********************************************
9 ( 45):*************************************
I have these arrays in a driver to use for testing:
insert Code:
#include <stdlib.h>
#include <stdio.h>
#include "TwoD.h"
int main() {
/* Initialization of LCV's */
[Code] ....
If I want to test these functions in this header:
insert Code:
#ifndef TWOD_H_INCLUDED
#define TWOD_H_INCLUDED
#define MAX_SIZE 50
/* Structure defenition for TwoD */
typedef struct
[Code] ....
I am trying to perform columnSum and rowSum, as well as twoDadd and twoDSubtract using the arrays defined in my driver. How would I do that using A and B in my driver?
How can we build unit-tests for functions of libraries, those with user-defined types used as their arguments ?
For example
CRecord func(Myclass * class, BSTR * name, CComptr<xxx> & something);
Did a little Googling on this but couldn't find anything definitive. Is it safe to do something like
Code:
void MyClass::myFunc(){
my_type_t &foo = some_obj->get_member_reference();
store_for_later(&foo);
}
Then at some pointer later in execution, another function uses the pointer passed to store_for_later.
I have the following code segment:
Code:
void Swap(Number& num1, Number& num2)
{
cout<<"Before swap:"<<num1<<" "<<num2<<endl;
Number& temp=num1;
num1=num2;
num2=temp;
cout<<"After swap:"<<num1<<" "<<num2<<endl;
}
[code]...
to which the output is:
Code:
Before swap:13 11
After swap:13 11
13 11 that seems confusing.
why doesn't Swap() swap the two Numbers?
I am trying to make a utility program for work that will update multiple projects with local dll references. Basically I work with two solutions (for talk sake solutIon1 and solutIon2). Generally solutIon1 will reference the dll's built In solutIon2 which reside on a server. However for debugging proposes I sometimes need to D/L the solutIon2 projects and build them local-ally, so that I can reference the solutIon2 dll's local-ally (this Is so that I can easily attach the dll and step Into the code). However this require changing the reference paths, so that I am pointing to the local-ally built dll's, which Is quite a laborious task.
So the question is how would I update references in solution1 from the program that I am making. I don't really know what to start reading about as I have never done anything like this before.
I am attempting to combine two vectors into a vector of pairs. I want to be able to alter the first and second of each pair and have those alterations reflected in the original vectors. I thought the following code might work but get compilation errors about a lack of viable overload for "=" for the line with the call to std::transform:
void f()
{
std::vector<int> a = {1,2,3,4,5};
std::vector<int> b = {6,7,8,9,0};
[Code].....
Is it permissible to declare, for example, `std::valarray<int&>`? If so, how do I initialize such if the `valarray` is a class member?
View 3 Replies View RelatedI have this basic prototype:
struct int_wrapper{int i;};
template <const int_wrapper&... IPack>
void display_all(const int_wrapper&, IPack...);
But when I try to compile it, the compiler says IPack is not a type on the last line. Are packs of references not allowed?
I was wondering if there is way to convert a C# class to its own project and it automatically keeps its references.
View 3 Replies View RelatedIs it possible to create a class that stores (non-const) references to some objects and enables users direct access by using range-based for loops on them?
Code: class container {
public:
void add(int& value);
void remove(int& value);
...
};
int main()
{
container c;
for (auto& value:c) {
// `value' should be accessible as type `int&' instead of being a pointer, `std::reference_wrapper<int>' or something like that
}
}
I'm having some problems in understanding how the code below works and why it produces the output it produces.. What I'd expect is that both functions, namely `add_1' and `add_2', would print the same output; but I've been proven wrong :/ So why does the second one get different memory addresses for the same variable?
Code should be self-explaining:
Code: template<typename... Types>
void add_1(Types&&... values)
{
// by the way: why do i have to use `const int' instead of `int'?
std::vector<std::reference_wrapper<const int>> vector{
std::forward<Types>(values)...};
std::cout << "add_1:" << std::endl;
for (const auto& value:vector) {
std::cout << &value.get() << std::endl;
[code].....