C++ :: How To Convert Velocity Vector To Speed
Feb 16, 2012Any example code to convert a velocity vector to speed in C++?
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C :: Prototype Function Square Root Velocity
Mar 30, 2013I am trying to computed the time it takes for a projectile to hit the ground. The problem is that i need to square the input of velocity before i do the calculation. the question I have is that if it's possible to have multiple arguments inside the brackets after main.
#include <stdio.h>
#include <math.h>
double distance (double a, double v, double g);
int square(int y);
double height(double v, double a, double g);
double time (double v, double a, double g);
double sqrt(double num);
[Code] ....
C++ :: Encapsulating Speed Types Of Different Animals
Nov 22, 2014#include <iostream>
#define show(variable) std::cout << #variable << " = " << variable << std::endl;
class LivingBeing {
protected:
struct Speed {
[Code] ....
Though the above works, memory is being wasted for speed types that do not pertain to many animals (a snail only crawls, a human never flies, etc...). Saving and loading their files will involve a lot of useless zeros. The problem seems simple, but I can't think of a good redesign to encapsulate speed properly for each of the many, many types of animals. Note that main() works with speed from the base class LivingBeing.
Should there be polymorphic Speed types within each Animal subtype? Then there will be a lot of identical Speed subtypes (e.g. many animals can only swim).
Something like:
class AnimalsThatOnlySwimOrCrawl : LivingBeing {
protected:
struct Speed : LivingBeing::Speed {
int swimmingSpeed, crawlingSpeed;
virtual void increase() override {swimmingSpeed *= 2; crawlingSpeed *= 2;}
[Code] .....
C++ :: Runtime Speed Integer Versus Double
May 27, 2013Using integers faster than using floating points? Or more precise: what do you estimate as the chance that writing a custom floating point class is worth the effort?
I need to examine some C++ code for an ARM7 or ARM9 processor. Instead of using floating points, the coder had chosen to use integers only. To be able to fake floating points, a custom class was written. The coder states that he avoids using floating points as these are much how much slower. "Have you measured this?", I asked. "No, but it is known to be so", he replied.
Google taught me that most people state integers are faster than using doubles, because their operations (addition, multiplication) take less assembler instructions. But if you need those floating points, what do you estimate as the chance that writing a custom floating point class is worth the effort?
C++ :: QLabels And High Speed Updating Causes Crash
Jun 26, 2014On a project I'm working on, I need to update many QLabels very quickly. Each label needs to be updated at about 20 to 50 hertz and there can be over 50 labels at any given time. The problem I'm having is after running the program for about a minute, the labels freeze and the whole program crashes about 10 seconds later. If I comment out the setText() and setNum() calls and reroute the outputs to the console, it runs fine and never crashes. Why does calling SetText() and setNum() so quickly cause the program to crash and how can I prevent this?
View 5 Replies View RelatedC/C++ :: Program That Monitors Downstream Speed Realtime
Feb 14, 2015I want to create a program in windows, it will search for a process/program by name or part of its name and monitor real-time at certain intervals the data speed at each moment that are received from the internet by this process/program. So that when no data is received by the process/program the speed will be zero and i will know it.
Can i do it in c or c++ , if yes then what libraries should i look into to do it and if i can not with these then what language and libraries should i look into to create the program?
C++ :: Processing Speed Of Rectangle Intersect Function?
Feb 20, 2014I'm trying to find the fastest method to find whether or not two rectangles intersect in an effort to streamline my code. I've built this function into a rectangle class I created below.
struct rectangle{
rectangle() :X1(0), Y1(0), X2(0), Y2(0) {};
rectangle(int X1, int Y1, int X2, int Y2)
:X1(X1), Y1(Y1), X2(X2), Y2(Y2) {};
[Code].....
C++ :: Speed Of Floating Point Multiplication / Division
Jun 2, 2012I heard that the speed of floating point multiplication is much faster than division. Is it still the case today?
View 14 Replies View RelatedC++ :: How To Control Speed At Which A Loop Loops Based On Outside Variable
Feb 20, 2015I'm using an animation program. In this program I've simulated a particle system. The particles are flying around at different and varying speeds. I've attached birds to the particles and I want to be able to control each bird's flapping animation based on its velocity; so birds moving faster will be flapping faster.
Initially, the bird's flapping animation is controlled by a parameter that goes from 0 to 100%. So not only do I need to drive the speed at which the animation goes from 0 to 100%, I need to set it on a loop so once it reaches 100%, it loops back to 0%. I'm extremely new to code so I don't think it would be wise for me to even provide a jumping off point, not that I could.
C++ :: Recursive Directory Scan - Can Use Multi-threading For Speed?
May 11, 2014In our Qt application, we have to load several files on application start-up starting from a root directory.
We are recursively scanning the directories and loading the files.
The total time it takes is about 12 seconds. Can we reduce this time if we use multi-threading?
I have heard that multi-threading does not work everywhere and it increases code complexity and debugging issues.
Would multi-threading solve the above problem? We want it to be platform independent (Mac, Linux, Windows).
C++ :: Class Template Convert Which Can Convert Itself To Any Data Type
Sep 23, 2012Code:
template<class T>
class Convert {
T data;
public:
Convert(const T& tData = T()) : data(tData)
[Code] ....
Why do we use operator? Is float and double function names below?
Code:
Convert<int>::operator<float> float();
Convert<int>::operator<double> double();
C++ :: Using Vector Push Back Function To Output Contents Of Vector (similar To Array)
Feb 9, 2015How 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].....
C++ :: Open File And Read In Rows To String Vector And Return Vector
Jun 7, 2012I 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.
C++ :: Create Class Vector As Template And Define Operations On Vector?
May 13, 2013I 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].....
C++ :: Recursive Function 2 - Create Vector Of Vector Of Integers
Mar 26, 2013Lets 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...
C++ :: Find Function To A Vector Of Structures Vector
Jul 5, 2013I 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.
C/C++ :: Cannot Print Vector Of Vector Of Doubles
Mar 31, 2014I 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?
C/C++ :: Swapping Vector Int And Vector Strings
Mar 30, 2013I 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] ....
C++ :: Can't Read In Matrix Into Vector Of Vector Of Int
Mar 24, 2012Code:
#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.
C++ :: Copy Part Of Vector 1 To Vector 2
Jun 21, 2012I am trying to copy vector to vector as follow:
Code:
std::vector<unsigned char> vec1;
//insert some values into vec1
std::vector<unsigned char> vec2;
Now I want to to copy 2 bytes from vec1 starting at index 5., why do i need to know how many bytes from the end of vec1?? can't i just specify how many bytes i want to copy from starting index?
std::copy(vec1.begin()+5, vec1.end()-??, vec2.begin());
C++ :: Converting 1D Vector Into 2D Vector
Apr 20, 2013Code:
#include <iostream>
#include <vector>
int main() {
std::vector<std::vector<double> > DV; //2d vector
std::vector<double>temp(8,0.0); //1d vector
[Code] .....
The conversion actually works but it does not give the expected the result. The output should be:
Code:
1 2 3
4 5 6
7 8
and it outputs:
Code:
123123123
C++ :: What Is Another Name For A Vector Inside Of A Vector
Sep 11, 2013What is another name for a Vector inside of a Vector. What is the name of this construct? Would it be a Constructor Vector? I think this is a trick question my teacher is asking...
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Nov 17, 2013I captured .ppm from avi file. How can I convert .ppm into .jpg only using C.
View 3 Replies View RelatedC++ :: Can't Convert To Hex
Mar 30, 2014I was assigned a problem involving using buffer overflow to access a different function than I was supposed to. I was able to figure out how to modify the point in stack that I need to change using a printf statement, however what doesn't make sense is that when I use the input "AABBCCDDEEFFGGx86x64x00x00" the stack changes to 78363878 I looked up the ascii codes and I assume that it's not converting x86, but using the input x86 instead.
View 4 Replies View RelatedC++ :: Can't Convert Char To Int
Nov 9, 2013I am writing a basic keylogger and i want to add data to log file, but it says that i cant convert char to int. Everything else works fine.
Code:
#include <iostream>#include <windows.h>
#include <stdio.h>
#include <time.h>
using namespace std;
[Code] ....
C :: How To Convert Char To Int
Nov 24, 2014Example
char A[4]
gets(A) --> 1234