Here is the code,
Code:
vector<int> vec;
for(int i=0;i<10;++i)
vec.push_back(i);
random_shuffle(vec.begin(), vec.end());
nth_element(vec.begin(), vec.begin()+7, vec.end());
No matter how I choose the second argument passed to nth_element, the elements in vec are always sorted as,
0,1,2,3,4,5,6,7,8,9
What is the use of second argument here?
I have to write an example in which you use a function having as argument a pointer passed by reference in C++. Can you provide an example like this:
funz.h : void funz( int *&a );
funz.cpp : ? (1)
main.cpp:
#include "funz.h"
#include <iostream>
[Code]...
as I write in (1) and (2) ?
write a code using vs studio 8 to read a diretory name as argument and then open the directory and read each file one at a time and find the match for a string passed as an nother argument in the lines of each file. When it matches create a file and write in that output file the file name whetre the match found, the line number and line which matched.
My vis does not have dirent.h. so please use another ways to read directory call witha system acll and then then extract the fienames in a file(use some primitive way to open the the directory)
I cant do this parts
(1) read a directory
(2) create a file with only file names
(3) read file names ans open the files one at a time till the end of the file reached
How to check the type of argument passed to each function, checktype, in below?.
void checktype(void *p)
{
}
or
template <typename Type>
Type checktype(Type t) {
}
I was having problems changing the value of my head node I passed it as an argument as head which would be the address. The parameter was defined as struct node *head. like this
bool deleteNode(struct node *head, struct node *delptr)
I tried manipultaing pointer values to change head node value but it did not work. I saw some code online which used pointer to pointers(in code below) to change head node value it worked I dont fully understand why. Would like better understanding of why.
Would also like to know why the argument call needed &head instead of just head.
remove = deleteNode(&head,found); opposed to remove = deleteNode(head,found);
#include "stdafx.h"
#include<iostream>
struct node{
[Code].....
I am posting this simplified piece of code that is a bit confusing for me. There are two functions that I call. One shows the expected results but the result of the other one rather puzzles me.
//#define defineVecTyp Vec3f
#define defineVecTyp float
template <typename vecTyp>
vecTyp buildLaplacianPyramid(cv::Mat inputmat) {
vecTyp lapPyr;
[Code].....
Calling the function sum1 does not change the values stored in the variables val1 and val2. The output of the program is as follows:
val1= 1 ## val2= 10 // before the call of function sum1
val1= 1 ## val2= 10 // after the call of function sum1
sumOfVals= 22
This is quite obvious and as expected and I just pasted this piece of code as an example for better clarification.
However, if I call the function buildLaplacianPyramid and apply a function for Gaussian Blurring, this also effects the cv::Mat passed to the function. The line imshow("M1, after buildLaplacianPyramid",M1); therefore shows an image that is blurred. Since I am not passing a pointer to the cv::Mat I do not understand why this should be happening. I was assuming that there would be a copy of the cv::Mat M1 to be used within the function. Therefore I was expecting the cv::Mat M1 to retain its original value. I was expecting that all changes applied to cv::Mat inputmat within the function would not have any influence on the cv::Mat M1. Just like in my other example with the sum.
So I have linked list and function which deletes element if next element is bigger, so my code is working but its not working with first element, in the comment I have wrote code which I would code for checking that first element, but when ever I check it is blowing up all program.
#include <iostream>
using namespace std;
struct llist {
int x;
llist *next;
[Code] .....
I have a pile of data, which i need to access frequently and fast. One entry consists of two unsigned ints, let`s call them source and destination.
One source can have several destinations, but this rarely ever happens. Several sources can have the same destination - this happens more frequently, but still scarcely.
Once the data is set up, it rarely ever changes - yet it should be possible to add or remove entries.
I now need to find all sources for a given destination, or all destinations for a given source.
The question: which stl container to choose?
I have tried a multimap, using the source as key. This works good for finding all d for a given s, but is inefficient in the other direction.
Do you think it would be more efficient to have two multimaps, sorted respectively by source and destination?
#include "stdafx.h"
#include "iostream"
using namespace std;
int main (){
int x;
int i;
int e;
[Code] ....
is the logic good ? and why the program is looping
I'm using waveinOpen to capture sound from my microphone. I know how to set how many channels to use, but how do you tell it what channel to use - left or right?
View 6 Replies View RelatedI am working on a program in C# that should make a user choose a specific path for the program to work.
The path they are choosing is a path for a game and from that selected path I use coding to load pictures from to the program.
Anyhow
I am able to make the user choose a path and save the selected path in a xml file.
But the user can select ANY path.
How could I do to make the user choose a specific path that I want them to choose?
I've just started using the CImg library and when I try to load a picture with this code:
CImg<unsigned char> image("example.bmp");
It works perfectly. But when I try to type in the image file name using the console it gives me errors. For example, if I try this:
std::string input_file;
std::cin >> input_file;
CImg<unsigned char> image(input_file);
It doesn't work. The way I see it, I should be able type "example.bmp" into input_file and use it but it doesn't work, and gives me the error:
"error: no matching function for call to 'cimg_library::CImg<unsigned char>::CImg(std::string&)"
I have included iostream and string.h.
I've read that we can write a program that displays a menu of commands for the user to choose from.We can write some functions that implement these commands, then store pointers to the functions in the array :
Code:
void ( *file_cmd[])(void) = { new_cmd , open_cmd }; // 2 cmd's for simplicity
We can get a similar effect with a switch statement but using an array of function pointers gives us more flexibility since the elements of the array can be changed as the programm is running.
I decided to write an example about this in order to understand better the context, I am facing some problems though :
Code:
#include<stdio.h>
#include<stdlib.h>
typedef void (*p_foo) (int);
void foo(int x);
void foo2(int y);
[Code] .....
The problems are :
Code:
TEST2.c:9: warning: initialization from incompatible pointer type
TEST2.c:9: warning: initialization from incompatible pointer type
TEST2.c:25: error: too few arguments to function "*(arr + (long unsigned int)((long unsigned int)i * 8ul))"
I am doing my assignment that will calculate total tax amount per day and per week and finally sum those up.
One of the requirement is to filter out any number in the array that is less than 1000 to be assigned a value of zero instead of the stored value so as not to add it in the calculation. How to fulfill this requirement.
Dynamic memory allocation in array in c programming. I am trying to make the user to choose the size of array they want to engage in the game.
However, i have remove the global variable which contribute the error to my code previously. Now I assigned all the arr individually but not using the global variable. However, i still not get the desired board i want. i still keep getting 9x9 array board.
And i also need limit the board size only from 4 to 9. And how do i do that.
Code:
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <conio.h>
#include <malloc.h>
#include <ctype.h>
#include <stdbool.h>
[Code] .....
I have a global list that contains smaller lists of char arrays. I have an issue where when I'm reading back the inner lists the last element of one list seems to point to first element of the next.
So my data looks like the below (values separated by commas with the pairs separated by tabs. The last pair in a line is the same as the first). When I read the first list back instead of seeing "456.678,678.98" as the last element in the list. I see "435.67,234.98" twice: at the end of the first list and start of the other. I have debugged when the list is populated and can see the correct values going in so I can't figure what's happening.
456.678,678.98 123.45,345.56 256.67,789.98 456.678,678.98
435.67,234.98 123.65,342.56 987.78,678.34 435.67,234.98
Code to fill the list:
obstacle_list = op_prg_list_create();
while (fgets(line, sizeof(line), obstaclePositions_traj_file) ) {
token = strtok(line, "
"); //Pull the string apart into tokens using the
input = op_prg_list_create();
[Code] ....
I have an std list of type double.. and the list is always guaranteed to have just 2 elements. I need to get the value of element 2 minus element 1. What is the least amount of code to accomplish that?
I tried this:
Code:
list<double> dList;
dList.push_back(1.0);
dList.push_back(2.0);
list<double>::iterator iter = dList.begin();
list<double>::iterator iter2 = dList.end();
double result = *iter2 - *iter;
But this code does not work. Why not?
I am currently having problems creating a loop that will allow my user to choose to return to the beginning of the program or quit.
#include <iostream>
using namespace std;
int main() {
int j;
do {float a;
cout << "+----Welcome to Basic Operations----+
| Select Your Operation |
[Code] .....
I have not yet finished designing the interface for a couple of the operations, but right now i am hung up on trying to return to the beginning. I believe it is because the j was defined inside do and isn't carried out of the do statement for while.
I am trying to create a program that reads my file filled with random words, it then compares the words after they are put into a 2d array and sees if there is any matching words.. unfortunately the count is not working for me (in function2 and function3) and I am not sure why..
Code:
#include<stdio.h>
#include<string.h>
char function1(char words_array[][17]);
int function2(char words_array[][17]);
void function3(int pairs, char words_array[][17]);
int main( void )
{ char words_array[20][17];
int x = 0;
[Code]...
I am writing a code that creates a deck of cards using a doubly linked list. One function, newDeck(), is made to create a new deck if the user wants. I don't have any problems creating the deck and it all seems to work fine, but when I run the whole program and a separate function needs to utilize the nodes in my deck, I get an error. Trying to find where there was a problem, I tried displaying the values of a card node in random parts of my code. At the end of the newDeck function, after the whole deck has been created, the card still displays correctly, yet when I return back to main immediately after newDeck has been called, I noticed that the values of my cards changed to either random values or they became null. I found this strange because in between the end of my newDeck function and at this point, there is no extra code so it doesn't seem as if there is any way the pointers could have been changed. Maybe It's because I don't have a complete understanding of pointers yet but is there any way that pointers can change values when returning from a function to main?
newDeck(head, tail, n); //this is how I call the function from main.
void newDeck(Card* head, Card* tail, Card* n) //this is my function body
{
for (int i = 0; i < 4; i++)
{
[Code]....
Draw the total of a passed value, or value in general, without checking how many values there are individually.
Here's a pseudo-example:
int aliens = 10; // This should be changed as desired.
void drawaliens(int value) {
aliens.draw(value); // Instead of having a test of how many to draw, draw the amount there is from one check
}
I want to draw the amount of aliens passed or called to the alien draw function.
However, I don't want the function to check every possible value of aliens which could be passed before drawing, and just check the value once and draw that value.
IF x ALIENS, DRAW x ALIENS instead of...
IF 1 ALIEN, DRAW ALIEN(1);
IF 2 ALIEN, DRAW ALIEN(2);
IF 3 ALIEN, DRAW ALIEN(3);
.... and so on.
If there can be hundreds of aliens, it seems impractical to check every single possible value before drawing, and just check the value and draw that value.
So here I have a program that is supposed to basically sort out who passed and failed. I am currently stuck on the switch statement, I'm trying to count how many students received an A, B, C, etc.
Here's what I have so far:
#include <iostream>
#include <fstream>
#include <iomanip>
using namespace std;
void printIdInfo(ofstream &fout);
void printColumnHeaders(ofstream &fout);
[Code] ....
I have a function :
void UpdateNotefications(vector <string> &Notefic)
Where I change a vector...
I called it with a thread :
thread t1 (UpdateNotefications, Notefic);
t1.detach();
Though I see that inside the func, Notefic has a val, and outside, it is still empty (after the function is over)...
I am going to read some codes about image processing and I need to understand functions like this one below?
BOOL Trans_Geo_Affine(CImage *pImgSrc, CImage *pImgDst, BOOL bMatrix,
BOOL bHvInversed, double fScale_xx, double fFlex_xy, double fSkew_yx,
double fRotate_yy, double fTx, double fTy, int nInterpolation, BOOL bResize, BYTE cFill)
[URL]
two parameters, CImage *pImgSrc and CImage *pImgDst. I think they are class pointers and the function is passed by reference. What should I learn to understand this function and its parameters? How should I use this function? how to use the function with two parameters CImage *pImgSrc and CImage *pImgDst.
I have this code:
tgaManager.fileWriter.put((unsigned char)min(blue*255.0f,255.0f)).put((unsigned char)min(green*255.0f, 255.0f)).put((unsigned char)min(red*255.0f, 255.0f));
that should pass the value decided by the min function to an ofstream object, filewriter, that call the put method to print chars in a tga image file. When I open the file, all I see it is a huge black screen. You may be thinking that the values of blue,green and red are all zero but it is not the case.
With this code:
if (x==50 && y==50) {
cout << "Min BGR: " << endl;
cout << min (blue*255.0f,255.0f) << ' ' << min (green*255.0f,255.0f) << ' ' << min (red*255.0f,255.0f) << ' ' << x << ' ' << y << endl;
I get: Min BGR: 9.54167 29.9188 47.8701 50 50
I have a list of Strings that are passed to a method consecutively by reference from a class. I want to get the string value passed to the method at a point in time. The reason is to perform an if statement.
//this is the class that holds that holds the constants.
using System;
using Microsoft.VisualStudio.TestTools.UnitTesting;
namespace xxx.Functional.xyz.Login {
public class Constants {
public static String Username = "paul";
public static String Code = "4";
[code].....