Suppose I have this vector it contains dates example
Vector.Dates [slot 1][slot 2] [slot 3] etc...
anyways slot 1 contains [ 05282013]
slot 2 contains [07032015]
I want to split the data it contains into 3 other locations How do I do that???
like vector.1[05][07]
vector.2 [28][03]
vector.3[2013][2015]
How do you only take partial data from a vector slot?
I'm new in IPC. I would like to implement a signal of a new message, which calls the slot function, eg .:
Code:
msg_on_newMessange(type, &slotFunction);
My code:
Header file: messages.h
Parent file: parent.c
Child file: child.c
How can I do this ?
I have a string like:
char *origin = "THIS, IS, SPARTA!"
What I want to do is get all characters in a string up to a certain delimiter, for that I've searched I can do that with:
sscanf
getline
strok
But what I don't know and haven't found is how to use these functions but to start reading from a certain position in the string. So I need to get the characters up to a comma but after "THIS," so that would be starting in position 5...
How could I do that? I tried using [x] in brackets but then it would just read a character...
I've been trying to create a templated class that takes a template as a parameter. I'd like to specialise this class for certain partial specializations of the template parameter but can't seem to figure out how to do it nor find anything online, (although I may be searching for the wrong thing).
As an example, say I have a class A that takes a template class with two parameters as its parameter:
template< template<class X, class Y> class Z > class A {};
I'd like to have a general version of A, for a general version of Z, but a specialisation of A for a specialisation of Z, e.g. where X is int but Y is still any type.
[URL]
#include <iostream>
#include <type_traits>
template<typename T, typename = void>
struct Test {
static int constexpr value = 1;
[Code] .....
Why does it output 1 instead of 2? How can I make it output 2 and still output 1 for e.g. Test<double>::value?
I want to write a template that combines two type of resources:
class someClasses {
typedef someType ElementType;
} template<class T1,class T2>
class combo {
...
}
And I want to specify my T1 and T2 has the same ElementType, how can I write my combo class to partial specialize the general case so the ElementType check is at compile time?
Calculated by the explicit scheme. Produces some very large numbers.
task:
[math] U_t = 3 (1,1-0,5 x) U_ {xx} + e ^ t-1 [/ math]
[math] U (0, t) = 0 [/ math]
[math] U (1, t) = 0 [/ math]
[math] U (x, 0) = 0.01 (1-x) x [/ math]
Need to find a solution with accuracy [math] 0.0001 [/ math] on the interval [math] T = 1 / a ^ *, where a ^ * = max a (x, t) [/ math] Plot graphs of functions [math] u (x ^ *, t), u (x, jt ^ *) [/ math] where [math] x ^ * = 0.6, t ^ * = T/10, j = 1,2,4 [/ math]
explicit difference scheme is as follows:
([math] $ u_t ^ {j +1}-u_i ^ j) / tau = 3 (1,1-0,5 x_i) (u_ {i +1} ^ {j}-2u_i ^ j + u_ {i -1} ^ j) / h ^ 2 + e ^ {t_j} +1 $ $ [/ math]
code of the program:
int main ( void ) {
setlocale(LC_ALL, "rus");
int I = 10, J = 30, i, j;
double T = 1.0/ pow(3.3, 0.5), h_x = 1.0/ I, h_t = T/ J, epsilon = h_t + pow(h_x, 2), c;
double **u = new double *[I + 1];
for (i = 0; i <= I; i++) u[i] = new double [J + 1];
[code]....
displays the following:
[URL]
I have this code that is supposed to store numbers in one vector and another vector stores pointers to the values in the first vector:
#include <iostream>
#include <algorithm>
#include <sstream>
#include <cstring>
#include <vector>
#include <cstdio>
[Code] ....
However, when I print out the values stored by the pointer vector, the first 2 values are not the same as what the input was. I have tried it with 4 - 10 values and always, the first 2 are not the same as the input but the rest are. I tried printing out the values as they are stored in the vector in the first for-loop and it seems to contain them all, but after that first for-loop, when I try to print *station.front(), it is now changed to something else.
input:
4
1231 234354 4544343 121312
output:
34144320 0 4544343 121312
input:
6
123 2435 353 12221 356567 4544452
output:
21704768 0 353 12221 356567 4544452
How can push data into the vector <list<Edge>> adjList? adjList[n].push_back (e);//gives error.
struct Edge {
int from_node_number;
int to_node_number;
int weight;
};
vector <list<Edge>> adjList;
Edge e;
for (int n=0; n< graph.size(); n++)
adjList[n].push_back (e);
Does it use Linked List or Dynamic Array?
I want to know this because if I happen to want to use a lot of insertions and deletions then it is more efficient to make use of Linked List instead of Dynamic Array.
While, if I happen to want to just access random parts of the Array, then Dynamic would be more efficient.
I want to make a 2D game using SDL engine and I need to check whether or not an object is colliding with a list of other objects. (because there would be more then one objects on the map.)
Since I would simply be accessing each object sequentially to check whether or not the object is colliding with another the object in question, and since any of those objects could "die" and be deleted at any time, it makes more sense to use Linked List then a Dynamic Array.
I am receiving packets of data from an ethernet cable. This is the line of code that is streaming in data from the ethernet cable:
size_t num_rx_samps = rx_stream->recv(&buff.front(), buff.size(), md, 3.0, enable_size_map);[code]
Here are the segments of me trying to push the packets onto a vector:
[code]
std::vector<size_t> processing_queue; //HERE IS WHERE I'M TRYING TO PUSH THE PACKETS ONTO A VECTOR
processing_queue.push_back(num_rx_samps);
[code]
I previously had my program saving to a .dat file (the commented out lines), but I need to change it to pushing values onto a vector so I can stream the data packets from the ethernet cable to be processed. However, the packets aren't being pushed onto the stack as I suspected. What do I need to change to push the data packets onto a vector? The following is the code:
[code]
#include <uhd/types/tune_request.hpp>
#include <uhd/utils/thread_priority.hpp>
#include <uhd/utils/safe_main.hpp>
#include <uhd/usrp/multi_usrp.hpp>
#include <uhd/exception.hpp>
#include <boost/program_options.hpp>
[code]....
If I want a class with a vector data member, can I specify it as follows?
std::vector< bool > integers( 101 )
I'm having some problems when compiling code.
I am receiving packets of data from an ethernet cable. This is the line of code that is streaming in data from the ethernet cable:
size_t num_rx_samps = rx_stream->recv(&buff.front(), buff.size(), md, 3.0, enable_size_map);
and here is my attempt to push it onto a vector:
std::vector<size_t> processing_queue; //HERE IS WHERE I'M TRYING TO PUSH THE PACKETS ONTO A VECTOR
processing_queue.push_back(num_rx_samps);
I previously had my program saving to a .dat file (the commented out lines), but I'm trying to change it to pushing values onto a vector so I can stream the data packets from the ethernet cable to be processed. However, I'm having issues with pushing the data packets onto the vector?
The following is the code:
#include <uhd/types/tune_request.hpp>
#include <uhd/utils/thread_priority.hpp>
#include <uhd/utils/safe_main.hpp>
[Code].....
I am having trouble putting data from a txt file onto a vector of a class. For instance.
class employee{
setname(string) {
some code
} getname () {
some code
} setid(int)
[Code] ....
How would use my setname function in my class using my vector? I tried doing vec[num].setname(tempname) but it doesn't work. I know it does not work because I have to use .push back for a vector but I don't know exactly how to pushback using the set name function call.
Overview of problem : I am using std::vector to hold objects of Subject. Now this vector contains lots of objects( with lots I mean 10-20 objects at max) . These objects have string member values like category and sub_category. Both category and sub_category can have string which can be same of other objects's sub_category & category.
Issue: Now I want my std::vector to have only those objects whose's sub_category are unique. If category is not unique that's not a problem .
Secondly if we found 2 objects having same sub_category then we have to delete one of them from the vector. we will delete it based on some rules example
Rules for deleting are if
i) instance of Subject ->category = " Land " OR if category = "Jungle" then delete other duplicate object ,
ii) if above condition doesn't match then delete either of them.
I am wondering , how would I compare the sub-items from the vector . For example. I have class say Subject
class Subject {
public :
// some constructors,
// functions to get ., set category and sub category
std::String get_sub_category()
std::string get_category();
private:
std::string category;
std::string sub_category;
}
I have vector which stores object of Subjects. Example : vector<Subject> copy_vector;
Now what I want is to delete the object from vector that has same sub_category I am not looking for source code buT i need a starting point,? Example:
copy_vector[0] = Animal object that has sub_category Tiger
copy_vector [1] = Animal object with Lion as sub category
copy_vector[2] = Forest object with sub_category Tiger
What I want is to based on some conditions(which I can do ) remove either Forest or Animal object containing Tiger. But for that how would I do comparison? I have written the function and have checked it.
std::vector< Subject >copy_vector;
// copy_vector contains all the objects of Subject with redundant sub_category
for( std::vector< Subject >::iterator ii = copy_vector.begin() ; ii != copy_vector.end() ; ++ii ) {
sub_category = ii->get_sub_category();
[code] ....
Two questions:
1. I have some vector<unsigned char> containing binary data. I would like to combine them into one std::string. How is the correct way to accomplish this?
This is my best guess for sample code:
Code:
vector<unsigned char> data; //conatins some data
vector<unsigned char> data2; //contains more data
string temp(data.begin(), data.end());
temp.append(data2.begin(), data2.end());
Will this code work with binary data, or will it null terminate?
2. A similar problem.. I have some unsigned char* variables, and I want to combine them into one std::string. How can I accomplish this? will the member append() work here? or will it null terminate? Something like:
Code:
unsigned char* data; //conatins some data
unsigned char* data2; //contains more data
string temp(reinterpret_cast<const char*>(data));
temp.append(string(reinterpret_cast<const char*>(data2)));
Will the above sample code work without null termination?
I am working on my second c++ project that is a statistical analysis of a vector data set of integers. I created a struct called range with a maximum value, minimum value and count for occurrence. The frequencies are stored in a vector<range>.
I have tried messing around with the increment to get the high range test above the maximum element, though my ranges cumulatively increase by 9.9. I'm not sure how the professor's program has the distance between high and low ranges as 10 instead of 9.9, which is the increment. I'm also unsure why half way through his buckets, the ranges appear as 9.99 briefly and then return to 10 after (40.00 - 49.99 then 49.99 - 59.99). I feel like I am missing something very obvious on line 04 or 10 in my code.
Here is the code for the frequency that accepts a vector reference for my data set of integers.
void frequency(vector<int>& data_set){
double max = findMax(data_set);
double min = findMin(data_set);
double increment = (max - min) / 10;
double percentage = 0.0;
[Code] ....
I have a generic template class with another template in one of its types. Now I want to specialize one of its methods for a particular (template) class, which leads to a compile error, however.
Here is the example:
#include <stdio.h>
template<typename Type>
class Obj1 {
public:
void ID() { printf("Object 1, size = %zu
[Code] .....
GCC ends with:
:35:27: error: type/value mismatch at argument 2 in template parameter list for ‘template<class Type, template<class> class O> class Foo’
:35:27: error: expected a class template, got ‘Obj2<Type>’
What is wrong with the specialization? Can it even be achieved and how (if so)?
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)
[Code].....
I have a cpp app that reads in a number of files and writes revised output. The app doesn't seem to be able to open a file with a ' in the file name, such as,
N,N'-dimethylethylenediamine.mol
This is the function that opens the file :
Code:
// opens mol file, reads in rows to string vector and returns vector
vector<string> get_mol_file(string& filePath) {
vector<string> mol_file;
string new_mol_line;
// create an input stream and open the mol file
ifstream read_mol_input;
read_mol_input.open( filePath.c_str() );
[Code] ....
The path to the file is passed as a cpp string and the c version is used to open the file. Do I need to handle this as a special case? It is possible that there could be " as well, parenthesis, etc.
I need to create a class vector as a template and define operations on vectors.
And this is what I made.
#include<iostream>
using namespace std;
template<class T>
[Code].....
Lets say that I have a vector of vector of integers. <1,2,3,4> , <5,6,7,8>, <10,11,12,13>
How do I make a function that creates vector of vector of every different integers?
<1,5,10> , <1,5,11>, <1,5,12>, <1,5,13>
<1,6,10> , <1,6,11>, <1,6,12>, <1,6,13>
<1,7,10> , <1,7,11>, <1,7,12>, <1,7,13>
<1,8,10>, <1,8,11>, <1,8,12>, <1,8, 13>
<2,5,10>, <2,5,11>, <2,5,12>, <2,5,13>
and so on...
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:
Code:
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
[Code] ....
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 am trying to print a matrix solution that I've stored in a vector of doubles. The original matrix was stored in a vector of vector of doubles. I want to print to the screen and an output file. Right now it just prints to screen column-style and the output file is horizontal-style. I tried to change the solution from vector of doubles to a vector of vector of doubles like the original matrix but when I run my code it crashes. Here is what I am referring to:
void readMatrix(vector<vector<double>> &matrix, vector<double> &b, int &N, string input) {
ifstream in(input);
in >> N;
matrix.resize(N);
b.resize(N);
[Code] ....
However when I change my printResult function to this (I removed the string argument because I just want to get it working to the screen first):
void printResult(vector<vector<double>> &sol, const int N) {
//ofstream out(output);
//int j;
for (int i = 0; i < N; i++) {
for (int j = 0; j < N; j++){
[Code] ....
The program crashes. Am I even printing the matrix correctly?
I want to have it so that when i ask for the person witch item they want to drop on the ground it goes into another vector that i can pick back up the item if they want it back and erase when they walk away.
#include "stdafx.h"
#include <iostream>
#include <vector>
#include <string>
#include <fstream>
#include <cmath>
using namespace std;
struct InventoryItem
[Code] ....
Code:
#include <iostream>
#include <istream>
#include <fstream>
#include <vector>
[Code]....
Why is it reading in nothing for the arrays, and also making the size of the total thing the total number of numbers? It should have a size of 2, not 5.