C/C++ :: Vector Contents Unexpectedly Different Within The Same Function
Jun 14, 2014
I am trying to create a tennis tournament simulator. There are 128 players in the tournament, and 32 seeds. I have a vector filled with 'Player' objects named 'Players'. Each 'Player' object has three member variables, Strength, Ranking, and ATPPoints. When the vector 'Players' is first declared, the default constructor for each 'Player' object is used, which initialises each of the 'Player' objects to zero. I then generate a Strength value in the range of 0-10 for each of these 'Player' objects, and sort them descendingly according to their strength.
I now want to create the draw for a tournament. I declare a vector 'Draw' with 128 'slots'. Each slot initially contains a blank 'Player' object, with its member variables set to 0. I first place the top 32 players throughout the draw such that they do not meet until later rounds as they would be in real life. For the remaining players, I position them in the draw by generating a random number between 0 and 127. Some of the slots 0-127 are occupied by seeded Players. These seeded Players have non zero Strength and Rank values, so to avoid overwriting these slots, I check the Strength value of the 'Player' object in the slot in question. A return value of 0 would indicate an empty slot.
At the beginning of the function, I output the Strength and Rank values of the 'Player' objects already in the draw. This outputs correctly.
for (Player& p : Draw)
{// outputs the draw in it's current state, with the already placed seeds as expected.
cout << p.GetRanking() << " " << p.GetStrength() << endl;
}
How to output vector contents using the push_back function. My program reads in values just fine, but it does not output anything and I've been stuck on why.
here is my code:
#include <iostream> #include <array> #include <vector> using namespace std; int duplicate( vector < int > &vector1, const int value, const int counter)
For the last part of this problem, if player 2 loses the game of hangman, I need to display the letters they did get right. In order to do that, I believe that I need to traverse vector v for the elements that exist in the string hiddenword, and then print those characters that match.
I ran into a problem while using while loop.T he declared and initiated local int variable works well with its specified value while running through the 1st run of a while loop. It is set zero while entering the 2nd run and the following unexpectedly. However, the variable still exits. The following is the code with problem.
Code:
#include <stdio.h> int main(void){ const int x=6; char c='y';
I am currently developing a sync module using asp.net. I am getting data from an external database (mysql database) The problem is I am getting the error "Connection unexpectedly terminated" when filling the dataset.
Here's my code
string P_contact = "SELECT A.id, B.firstname, B.middlename, B.lastname FROM Accounts A, Contacts B WHERE A.id = B.id"; MySqlDataAdapter db_P_contact = new MySqlDataAdapter(P_contact, conn); DataSet ds3 = new DataSet(); DataTable dt3 = new DataTable();
In the function *expandArrayList and *trimArrayList I need to allocate either more memory or less memory to the given array. Right now I am using malloc on a new array and then transferring the elements of the original array to the new array, freeing the original array, and then reassigning it to the new array so it's size and capacity are either bigger or smaller than the original. I feel like there has to be a simpler way to do this with either realloc or calloc, but I cant find sufficient information on either online. Would I be able to use either to make this easier and the code cleaner?
Also, these are character arrays that contain several character arrays inside them, so I was wondering what the best way to transfer the contents of one array to the other would be. I have gone between
Code:
//example for (i=0; i<length; i++){ newarray[i] = oldarray[i]; } and Code: for (i=0; i<length; i++){ strcpy(newarray[i], oldarray[i]); }
but I'm not sure which one (if either) should work.
The 'ArrayList.h' file that is included contains the structure ArrayList, as well as the function prototypes for the functions listed below.
Here is the structure in ArrayList.h:
Code:
#define DEFAULT_INIT_LEN 10 typedef struct ArrayList { // We will store an array of strings (i.e., an array of char arrays) char **array;
I have function which will replace (or create) an file with the contents of another stream. The stream could be anything. The replacement is done safely.
Code: #include <errno.h> #include <stdio.h> #include <stdlib.h> #include <limits.h> #include <unistd.h> int do_replace(const char *file, int stream, int cnt) {
So I insert values from a vector into a list and into a multiset, and I noticed zero is added to their contents! I had to do a whole lot of debugging to find out where the error was, how can i stop this thing? Code which generates such error...
infact i checked the content of vector ups to be sure that there was no zero in it, but after loading into list combi_t * head, it seems like there was a zero added and this is giving me errors when i call function master_roller...
Code: void ins(combi_t * &testa, int &numero, int &num, int &no) { // if (ricerca(testa, numero) == 0) //{ combi_t *temp = new combi_t;
I have asked a related question before, and it was resolved successfully. In the past, when I wanted to use std::max_element in order to find the maximum element (or even sort by using std::sort) of a vector of structures according to one of the members of the structure, all I had to do was to insert a specially designed comparison function as the third argument of the function std::max::element. But the latter comparison function naturally accepts two arguments internally.
For instance, here is a test program that successfully finds the maximum according to just one member of the structure:
And the output was this, as expected: Maximum element S.a of vector<S> vec is at: 9 [I]max element of vec.a between slot 3 and slot 6 is: 6, and its index is: 6 vec[6].a = 6 [I]max element of vec.a between slot 4 and slot 7 is: 7, and its index is: 7 vec[7].a = 7 [I]max element of vec.a between slot 5 and slot 8 is: 8, and its index is: 8 vec[8].a = 8 [I]max element of vec.a between slot 6 and slot 9 is: 9, and its index is: 9 vec[9].a = 9
However, I now need to search and find an element of vector<myStruct> according to just one member of myStruct, instead of finding the maximum or sorting as before. This presents a problem because the function std::find does not accept such a comparison function as its third argument.
This was the description of the std::find function that I found: find - C++ Reference
Code: template <class InputIterator, class T> InputIterator find (InputIterator first, InputIterator last, const T& val);
I could also find another function called std::find_if, but this only accepts a unary predicate like this: find_if - C++ Reference
Code: template <class InputIterator, class UnaryPredicate> InputIterator find_if (InputIterator first, InputIterator last, UnaryPredicate pred);
And once again this is either inadequate of I don't see how to use it directly, because for the third argument I would like to insert a function that takes two arguments with a syntax like this:
Code: int x=7; std::vector<S>::iterator result; result = std::find(vec.begin(), vec.end(), []( const (int x, const S & S_1) { return ( x == S_1.a ) ; } ) ;
Is there another std function that I can use to make search and find an element according to just one member of myStruct?
Or perhaps there is a clever way to pass two arguments to the unary predicate.
I have a modal dialog. When I click on a button in the dialog to perform an operation, a non-modal dialog is displayed showing a progress message.
The operation is not successful. It calls WaitForSingleObject and times out. This seems to have an adverse effect on the modal dialog, which strangely becomes non-modal.
The first line displays the modeless dialog. The second line performs the operation, which calls WaitForSingleObject. And the last line destroys the non-modal dialog.
I am writing a function to take two vectors and put them end to end in a third vector. I'm new to working with vectors, and I cannot figure out why my append function is not returning vector C. I had the function print out vector C within it to make sure the logic in the function wasn't the problem, and it worked perfectly. My code is as follows:
#include <iostream> #include <vector> using namespace std; //append function to put vector b after vector a in vector c vector <int> append(vector <int> a, vector <int> B)/>/>/> { vector <int> c;
[code]....
and my output is as follows:
Vector A contains: 10 18 123 172 Vector B contains: 283 117 17
The two vectors back to back are:
Obviously, the third vector is not returning from the function to main properly, but why.
writing a sorting function that has an argument for a vector of ints rather than an array; it should use a selection sort algorithm.Here is what I have:
#include <iostream> #include <vector> #include <conio.h> using namespace std; void fillVector(vector<int> &aVector); // PRECONDITION: number declared size of array a. // POSTCONDITION: number_used is the number of values stored in a //a[0] through a[number_used-1] have been filled with nonnegative int.
I'm trying to do is write a program that fits to a separate test program. The test program provides different size vectors that my function should try and binary search. If the element is found, the function should return 1, and if the element is not found, it returns -1.
Here is the code:
int binSearch(const vector<double> & data, int elem, int & comps) { { int beg=data[0]; int end=data[data.size()-1]; int mid=(end+beg)/2;
[Code] ......
The problem is that one of the vectors my function is supposed to binary search is a vector of size 0. I tried to throw in an if statement that would return -1 if the size was == 0, but then the program never fully completed and just kept running. So, how can I account for a size 0 vector in my function?
I defined the following function to find out the iterator of a certain value in the vector. I defined it as such so if the value exist in the vector then return a iterator of it, if not then return a pointer pointing to nonsense.:
I need to iterate through a vector in a const function, and, as my function is called very often, to get more performances I need my iterator to be declared somewhere else than the function, so it doesn't have to get deleted and recreated over and over again. So here is my code:
std::vector<double> calculate_mag_response(double start_freq, double end_freq, int N, std::vector<double> num, std::vector<double> den
The function should return a vector size N of magnitude responses in decibels of the transfer function defined by numerator and denominator vectors num and den. To adequately test, you should drive this with more transfer functions.
#include <vector> #include <iostream> #include <cstdlib> #include <ifstream> using namespace std; int main(int argc,char *argv[]) { vector<double> myNum, myDen, results;
I am having a problem with a program. I have a bunch of classes all derived from the same base class. I want to loop through a vector of objects, calling a function in each. The problem is that it doesn't matter which class the objects are, only the function defined in the base class is called.
I simplified the code as far as possible to replicate the problem. As you see, I would like a mix of numbers 1,2,3 as the output, however using the vector the only number output is 1. Here is a copy of the output by the way:
I suspect this is the "slice" problem, because the vector is defined with pointers to the base class so it uses the base class functions? The question is how to get around it? How can I loop through a vector of objects sharing the same base class but calling each by their correct member functions?
Code: #include <iostream> #include <vector> class Base { public: int num() { return 1;}
// Creates a generic entity in the entity pool void EntityManager::CreateEntity() {
[Code] .....
In this case it checks the entity pool for an entity, if one exists it moves it to the active entities and then returns the unique id, if one doesn't exist it creates one then calls itself to run the check again to verify and move the new entity.
My question is, is this a valid form of recursion since it only incurs a single loop of recursion, or should I reform the entire system to work differently? If so, how do you set this up in a way that does not cause recursion?
Okay, so for an assignment I need to write a function called find() that returns a reference to a vector. So I have vector <int> & find(string & key); If I do this, I get the obvious warning warning: reference to local variable 'lineNum' returned [enabled by default].
If I do vector<int> & find(string & key) const; I get a huge error that starts out like
In member function 'std::vector<int>& index_table::find(std::string&) const': indextable.cpp:74:30: error: no match for 'operator='
"Write a declaration for a function that takes two int parameters and returns an int, and declare a vector whose elements have this function pointer type."
I am writing a raytracer, and currently I'm working on creating a bounding volume hierarchy to accelerate the process. To do this, I am first creating a vector that holds each of the objects in the scene, and passing this vector to the constructor for my BVH.
Code: //in header BVH_Node* bvh; //in main raytrace function
[Code] .....
I am testing a scene that has only 2 objects, and so it goes to the size == 2 check. The first time it hits makeLeaf(), I segfault. I've used both gdb and valgrind, and of course it's a memory mapping error. gdb's backtrace tells me that the length of the vector I've passed in is -805305610 and the capacity is -21, and that it is inside my makeLeaf() function that the error occurs.
