C++ :: Class Creation And Storing Angles
Dec 22, 2013
I have a quick question. I need a way to represent orientation in degrees. I made a class which automatically changes negative angles into positive ones (adds 360 until >0) and makes sure they are under 360 (subtracts 360 until <360).
Now I realized I also need a class to represent angular movement, which must be in the range ]-360;360[
I don't think custom types with the unsigned keyword is a thing, but I'm just looking for a better way to do this then making two classes. Or would you just create a class which inherits from angle and overloads a few methods?
Or I could just use floats to represent rotation, because testing if an object does more than 1 turn per second isn't really required.
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Oct 11, 2013
I am drawing in a simple (square) MFC window. I realize that (0,0) starts in the upper left hand corner. I wanted to see how MFC handled drawing of angles, so I use this code:
Code:
double CompassDegreesToRadians(double compassDegrees) {
return((PI / 2.0f) - (compassDegrees * PI / 180.0f));
}
// Make pen
CPen penRed;
penRed.CreatePen(PS_SOLID | PS_COSMETIC, 1, RGB(255, 0, 0));
// Test Angles
[Code] .....
Using this code, and changing the value of angle1 to these values (0, 90, 180, 270) I think MFC uses the coordinate system:
Code:
180 -y
|
|
-x 270---------------- 90 +x
|
|
0 +y
This seems like a strange coordinate system to use. Am I doing something wrong? If this is correct, how can I convert my calculations to this coordinate system? (compass degrees):
Code:
0 +y
|
|
-x 270---------------- 90 +x
|
|
180 -y
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May 8, 2014
Given an array of angles A = [0 30 60 90 120 150 180 210 240 270 300 330 360]
Write a program that will generate the data set of angles automatically and provide three columns; sin(angle), cos(angle), tan(angle). Make this program as compact and readable as possible.
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May 2, 2013
How do I go about storing info to an array of class?I need to do something like this:
info[count] = ReadNameRating(n, r);
Where info is an array of my own class and ReadNameRating reads the name and rating which is two of the variables handled by that class.
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Apr 23, 2013
I am currently stuck on what I should do next in a program I am working on. These are my instructions:
Design, implement, and test a class for storing integer arrays "safely". The array should be able to hold any number of integers up to 100.
In the class header file "SafeArray.h" students must define the class and specify the constructor/destructor functions, the public methods and private variables. In the class implementation file "SafeArray.cpp" students must implement the following operations:
constructor - to initialize the object.
copy constructor - to copy an object.
destructor - to delete the object.
set - allow the user to set a value of the array at a particular location.
get - allow the user to get a value of the array at a particular location.
print - print out the array.
add - add the elements of one array to another.
subtract - subtract the elements of one array from another.
The output of my program is suppose to look like this:
Set q1: 2, 3, 4
Print q1: 2, 3, 4
Set q2: 1, 4, -2
Print q2: 1, 4, -2
Add q2 to q1
Print q1: 3, 7, 2
Get q1 at 1: 7
Here is the code I have so far.
*main.cpp*
#include <iostream>
#include "SafeArray.h"
using namespace std;
int main() {
// Declare a SafeArray object
Safe obj;
[Code] ....
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Aug 18, 2013
I've a text file : Random.txt which comprises of
Jade
12MS234
Male
18
Rocky
12MS324
Male
18
Marx
12MS632
Male
18
Now in my program i've a class
class stud
{
char name[10];
char reg[10];
char gender[10];
int age;
};
Now I've to write a code in c++, where i've to read the given data and store this into 3 objects of stud class(array of objects) ...then further i've to manipulate the above stored data. I think i'm getting error while storing...variables are showing random characters... give me the code.for this program..in C++
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Nov 17, 2014
Im trying to make a c++ program for a school project, and i need to store the information into binary files, but I'm having some problems trying to store a class with string members, for example:
class whatever{
protected:
string name;
public:
(List of functions)
}
But if I do that, my code just dont work when I write and read a binary file, but if I change the string to char array, for example:
class whatever{
protected:
char name[20];
public:
(List of functions)
}
It works good, so I wanted to know if there's some way to store a class wiht strings in binary files, or what am I doing wrong?
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Oct 9, 2014
In VC++ is there any inbuilt class for storying values inside an XML File, without using CLI?
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Mar 4, 2014
I need to create dynamic array or map. for example
CString *a1;
CString *a2;
CString *a3;
it minimized to using for loop.
for (int i=1;i<=3;i++) {
CString s="a"+"itoa(i)"
CString *s;
}
Something like this. its same as map concept.
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Mar 31, 2013
I have a basic query regarding GUI Objects (Labels, Combo Boxes etc) creation and deletion in a Dialog Box / Window. If I have the following code:
void MyWindow::someFunction() {
Label* myLabel = new Label(this); // how is it different from just "new Label";
//some code using myLabel;
[Code]....
1. Will myLabel (the object, not the pointer) be visible to me in the nextFuntion?
2. Is it necessary to call delete for the objects that I created in someFunction or are they cleaned up automatically by the compiler?
I am using Qt Creater as the IDE.
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Oct 15, 2013
How I can implement it.
Tickable.h
#include <list>
#ifdef TICKABLE_EXPORTS //Automatically defined by MSVS
#define DLL __declspec(dllexport)
#else
#define DLL __declspec(dllimport)
#pragma comment(lib, "Tickable.lib")
#endif
class DLL Tickable{
[Code] ....
error LNK2001:
unresolved external symbol "private: static class std::list<class Tickable*,SKIPPED BITS> Tickable::subs" HUGE_SYMBOL_LIST
PATHTickable.obj
I know with such a tiny and insignificant class the dll export seems pointless but this class is actually intended to be a .lib ONLY. But it is derived from by .dll style classes, and through inheritance this error is the exact same as what appears in the derived class, I just imagine that the cut down version would be easier to work with.
Is it possible to hold either a static variable in a dll which is of a dynamic type, OR would it be possible to reference an external variable which is static throughout the instances and this variable can be chucked away in a namespace of mine somewhere?
I suppose my only other option (if this is possible) would be to define a maximum instance number and create a standard array of pointers but this could both waste so much memory when not in use and cause problems if I need more memory.
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Apr 29, 2014
have a piece of code
for (int i = 0; i<5; i++)
{
CMyStackObject sobj;
//
...
}
Does standard guarantees that instances of sobj will be different for different i?
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May 19, 2013
I'va got a segmentation problem with creation of core dump for the following snippet of c code:
Code:
#include
#include
#include
"lezione.h" studente s1, s2; studenti s;
int main()
{ int codice; char* nome; char* cognome; int esami;
printf("Leggi uno studente da tastiera e memorizzalo in una struct
");
lettura_studente(s1, codice, nome, cognome, esami); return 0;
}
[code]....
In conclusion I'va two problems:
1) Program crash;
2) I can't read struct studente within parameter function. What are the problems?
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Jan 24, 2014
I see many time where static data member is used to count creations of objects -
i.e.
1. the static data member is init to 0
2. the static data member is incremented by 1, in the Class' constructor, every time an object is created
However, if you define a global object of a class,
How can you tell that the static data member is initialized BEFORE the constructor of the global object is called? (i.e. before the global object is created).
Because to my understanding, you do not know in advance the order of global objects' creation -
so the Global Object could be created BEFORE the static data member was created and initialized.
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Mar 2, 2013
This problem is best explained by looking at its output below. I stored 15 different values but when retrieved some are wrong.
#include <iostream>
using namespace std;
class A {
public:
int ** pointer;
[Code] ....
I need to store and retrieve the 15 different values correctly. How to solve this? The main thing is, I need to store the pointer in class A objects.
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Apr 15, 2013
I'm trying to write a function that takes a 32bit address and a data to store at this address.
I'm wanting to take the 32 bit memory address eg 0x12345678 and split it
into 4 x 2 bytes
12, 34, 56, 78
then each of the 4 entries is at most a 256 entry array.eg
FF, FF, FF, FF
So in this example, 0x12 points to 0x34 in the second array, which points to 0x56 in the third array, which finally points to 0x78 in the last array. This last array holds the actual data.
After successfully doing 0x12345678, say I might get a read for 0x1234AABB. So, the first and second pointers already exist, but I then have to create and write to dynamically created arrays.
The arrays need to have all entries set to NULL so that i know whether to follow the pointers to overwrite a previously entered value or create new arrays and pointers.
It all looks good and simple in the pseudo code I've written up but I'm having trouble coding it. I'm currently trying to deal with the first entry case, ie all array elements are NULL, but I'm getting confused with the pointers and creation of new arrays.
void cpu::store(unsigned int mem_add,unsigned int mem_val) {
int first = (mem_address&4278190080)>>24;
int second = (mem_address&16711680)>>16;
int third = (mem_address&65280)>>8;
int fourth= (mem_address&255);
[Code] .....
A1 has been declared as
int* A1[256] ;
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Mar 26, 2013
I have a project to do in C and coming form Java I miss all the included features that are missing from C! I need to be able to store key value pairs in an quick and memory efficient manner. I've looked up using hash maps but I'm very new to C so don't really understand even the basic ones. I've looked at using a multi-dimensional array as I'm more comfortable with arrays but I'm unsure if that would count as a memory efficient and quick method?
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Feb 5, 2014
So i'm creating bank system. Where I have function that reads the text file (balance), and I make a deposit, which adds what was in the balance = deposit + balance.
But this is what is happening. In my text file i have number 10. Function balance works fine and reads 10 from the text file.
When I make a deposit add a value to the balance, if i add 7, the new balance is 17. And i check the text file shows me is 17. Which is correct.
The problem is here. If i make another deposit, without closing the program, for example i add 5 to the balance, the new balance should be 22 = 17(balance) + 5(deposit), because 17 was store on the text file and it was the balance that was store on the text file on the last time. But it shows me 15, it adds the balance that the program first started which was 10(balance) + 5(deposit), but should had had be 17 + 5.
When I close the program the value on the text file, is 15, that was the last sum that i did.
int main()
{
double balance = 0;
balance = currentBalance(balance);
menu(balance);
[Code].....
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Mar 29, 2014
I am doing this program where I analyze colors in a ppm file. Now I am having a hard time storing the data into arrays in this order...
P3
600 339
255
44 5 8
44 5 8
43 4 7
42 3 6
42 3 4
44 5 6
...
So far i tried using fscanf()
Code:
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <stdbool.h>
#define DEBUG true
#define CHECK true
[Code] ....
I then realized that the order that the second method gave me will make it very hard for me to calculate the RGBs. Because they will be calculated like wise..
P3
600 339
255
44 5 8 = sum
44 5 8 = sum
43 4 7 = sum
42 3 6 = sum
42 3 4 = sum
44 5 6 = sum
...
but that isn't the issue right now..
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Dec 9, 2014
I wanted to find all the prime until a specified limit in C. I use the Sieve of Eratosthenes. But when I define the limit to anything more than a 7 digit number the program terminates.
Code:
#include<stdio.h>
#define limit 1000000000
int main(void)
{
unsigned long long int i,j;
int primes[limit] = {0};
//int count =0;
for(i=2;i<limit;i++)
}
[code]....
I believe that this might be because the size cannot be declared array cannot be more than the a 7 digit number. I think so. how to store a 10 digit number in C?And can't unsigned long long hold a 10 digit?
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Mar 27, 2013
I am having trouble storing strings into an array. Basically I have a console program where it has an option. This is just an example;
Code:
char name[max];
char listofnames[maxname];
int counter;
....
printf("Add names
");
And how can I print it?
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May 4, 2013
So i have a program with the structure
Code:
char record[20];
typedef struct{
int id;
char title[20];
char subject[20];
char faculty [20];
int level;
char fname[25];
}report;
int recno,i;
report list[100];
I need to store the hundred records into a file. What are the functions and elements i should use/introduce.
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Oct 17, 2013
I have a file that can range from 100 rows to 10000+ that is comma delimited with 8 columns. The first 32 rows (also comma delimited) will always be ignored (geographical header information). I will be wanting the data from column2 and column3.
For this I believe I would need (2) For Loops as such:
for(i=0;i<2;++i) {
getline("do something here");
}
and
for (i=0;i<3;++i) {
getline("do something here")
}
Also would using a vector or array with dynamic storage be the better way to tackle this problem? Where to start from after accessing the file.
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Mar 27, 2013
Is it possible to store data to CPU memory, if so how much memory can I store and how? Say I wanted to store an array, about 6MB in size?
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Sep 27, 2013
I have a base class Building. Then come its children classes - Commercial Building and Residential Building. The third level is composed of Apartment and House classes, both inherit from Residential Building.
I need to create an array of 20 elements that will store info about all these different types of buildings(Commercial Building,Residential Building,Apartment, House). How should I proceed?
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Oct 31, 2014
I have two classes, Parent and Child, where Parent contains a vector that is used to store instances of Child. When I create an instance of Parent, three instances of Child are also created in Parent's constructor and stored in the vector. I understand that push_back() creates a shallow copy of each Child instance and that Child's destructor is called each time the loop (inside Parent's constructor) iterates. The problem is that because Child's destructor is called each time the local variable child goes out of scope, the memory previously allocated in Child's constructor is destroyed and when Child's destructor is called again later on in the program to get rid of the copy stored in vector, the program crashes. I can fix this by overriding the default copy function or by storing pointers to objects instead of copies of objects. I don't really need to use vectors in this case since I always have three children in one parent but I'm doing this as a learning exercise and would prefer to use vectors.
#include <iostream>
#include <vector>
class Child {
public:
Child() {
std::cout << "child constructor called" << std::endl;
[Code] .....
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