C/C++ :: How To Create A Vector In Header File That CPP Object Can Use
Apr 25, 2015
I'm working on a grocery store inventory project. One part is to have a shopping cart, where customers can put in up to 20 items. Because there can be up to 20 shopping carts at one time, I want to use a vector inside the cart object to represent all the individual food items.
Here's my code,
Header:
#ifndef CART_H
#define CART_H
#include <vector>
class Cart {
public:
Cart();
Cart(std::vector< int >, std::vector< int >)
I need to use an instance of an object in a header file. The object requires a lot of pre-computation to be created.
I want to assign it to a "static const *NAMEobject*" field in the .h file, once it has been created. I assume that it is better to create it in another file and somehow pass it into the .h file.
Let's say I am using a library containing classes called class1 and class2 but both classes take three arguments to construct them. eg. class1(int a, int b, int c). and the same for class2
The below is an example of how to lay out the structure in the header and source file if class1 and class2 don't have any arguments in their constructor. But.... I'm not sure how to go about the below to take into account the constructor arguments of class1 and class2.
I have a header file in which we include vector at the top. But we want to remove that include. On doing so I get compilation errors as the header file uses std::vector<> at several instances in header file so I have to forward declare the vector to solve this issue.how i can do it.
I am a beginner with C++, taking a class right now. The lab this week is to create a user defined class and have it accesses in a separate .h header file from the main.
I think I'm finding my way through it, but I'm getting a complie error that makes no sense to me:
I have a school project in which need to create a function that takes a File Object as a Reference Parameter. Supposedly, it should allow me to read the first piece of data from others separated by a space from a file. The later be able to continue reading from the next piece of data.
I know how to set things up to read from the data file, such as using
In 32bit, the object header size is always 8bytes. In 64bit, the object header size is always 16bytes.
Is this safe to assume or are there situations where the header size can be smaller/larger than the numbers above?(Haven't found anything on this, so I assume no?)
I need to know the exact size of the object header, because I need specifically pad a few classes I wrote to avoid false sharing along cache lines. Just need to make sure I have the sizes correct so I don't pad them wrong!
I want to create a welcome text header during the program runs. I wanna keep it at the top while the program is running (like asking for input@ showing output).
EG: ----- WELCOME ----- //Stay until end of the program // output/input. "WELCOME" stay at the top
I have an assignment that asks me to implement a variant of the classic bouncing balls program.
'Each ball should start off at the top of the screen with a random speed in the x direction. Whenever a ball hits a screen boundary it should bounce off at an angle equal to the impact angle and lose some speed. Eventually each ball should come to a rest at the bottom of the screen. Five seconds after coming to a rest a ball should be removed from the screen.'
'Your code must keep track of objects (balls) by placing the object data structures in a linked list. You need to create your own linked list implementation. Below is a brief description of the object programming interface: CreateObject - Create a new object. The function accepts as input parameters a pointer to the SDL screen, a pointer to a model triangle array, and a variable telling the size of the model triangle array. The function returns a pointer to a new object data structure. The model triangle array specified as input parameter should not be shared across objects. (Not sharing the model triangle array allows e.g. objects to have different colors.)
Perform the necessary memory allocation and copying.DestroyObject - Free object. The function accepts as input parameters a pointer to an object data structure. The function should free all memory allocated to represent the object (memory allocated for the model triangle array and the object data structure itself).
Drawobject - Draw object on screen. The function accepts as input parameters a pointer to an object data structure. The function must draw the object on the screen by calling DrawTriangle on each of the model triangles. Remember to update scale, translation, etc., in each triangle data structure before invoking DrawTriangle.
Hint: Do not make the bouncing algorithm too complex. Bouncing a ball off a vertical or horizontal surface can be accomplished without resorting to calculating impact angles.'
The function I'm stuck at, is the first one - createobject.
I'm new to C++ especially vectors.. I've a question regarding sorting of object in a vector.. My object consists of x,y and civ. so I would like to know how do I sort the value of the civ in an descending order but at the same time retaining the value of x and y attached to it..
I am erasing a object from the vector. I want to know that do i need to delete the object before I call the erase method or calling the vector erase method is suffice. See the following example.
Class A { int val; };
Class B { vector<A *> vectorA; void AddA(int val) { A *a = new A; a->val = val; vectorA.push_back(a);
[Code] ....
I don't know which DeleteVectorEntry to use which makes sure that there is no memory leak in my program.
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?
case DELETE_TITLE: std::cout << "Game to remove from list: "; std::cin.ignore(); getline(std::cin, gameTitle); for (iter = gameList.begin(); iter != gameList.end(); ++iter) {
[code]....
It deletes the text from the string but not the index it self.
It deletes the text but when I print the list of game titles it has it there blank. I want it to completely remove the object from the vector from where it was deleted
