How we can return a 3x3 matrix in c++ function.
My code is:
double *computeA() {
double *A = new double[2][2];
// some operations on A and then return
return A;
}
The error that I have in this case is:
error C2440: 'initializing' : cannot convert from 'double (*)[2]' to 'double *'
How can i returns the address of the matrix.
The Question : Complete the following function that takes 2 integers m and n as parameters. The function defines a dynamic matrix of integers of size mXn, fills the matrix with information from the KB, then returns the address of the matrix.
Note: DO NOT forget to put the returned datatype in the given space(………….)
………………………. allocate (int m, int n) { }
My solution :
int allocate (int m, int n){
cin>>n>>m;
int **a;
a=new int *a[n];
for (int i =0; i<n; i++)
a[i] = new int[m];
for (int i=0; i<n ; i++)
for (int J=0; j<m ; j++)
cin >> a[i][j];
}
I'm writing some functions pertaining to binary trees. I've used recursion once before while learning quicksort but am still quite new and unfamiliar with it. And this is my first time touching a binary tree. So my question: In my addnode function, will the return root statement at the end ever return a value other than the value passed to the function?
Code:
#include <stdlib.h>
struct tnode
{
int data;
struct tnode * left;
struct tnode * right;
}
[code]....
i need a function that will work for both dynamic and static implementations of a function to get the transverse of a matrix. so far, i have this
Code:
matrix transpose(matrix m)
{
int row, col;
row = m.com_dim;
col= m.row_dim;
}
[code]....
this works well with my static implementation, but when i try it in dynamic it gives me errors. the function has to be the same for both dynamic and static implementation
I'm trying to pass 2 arrays into a void funtion, and return values to one function.
this is the the program I'm working with, after I'm done I have to split it into 3 files, a header, a main, and a separate cpp file for the functions to live in.
#include <iostream>
using namespace std;
void processArrary(int numberCount[], int Numbers[], int intnumberSize, int numberCountSize);
int main() {
int Scores[26] = {76, 89, 150, 135, 200, 76, 12, 100, 150, 28, 178, 189, 167, 200, 175, 150, 87, 99, 129, 149, 176, 200, 87, 35, 157, 189};
int numberCount[8] = { 0 };
[code]...
The goal of this program is to separate and count the groups of numbers then output the amount of numbers in each group. Near as I can tell, everthing should work, but I'm getting all zeros to be displayed in each group.
The function is supposed to return value from the file in my main, but I am getting empty value. I am trying to get better with pointer. Right now just teaching myself.
right now the only way for this code to show value is when in put the putchar(*ps) inside my readfile function. I would like to readfile to return value and print in the main function.
Code:
#include <stdio.h>
char *readfile(char filename[]);
int main(int argc, char *argv[] ) {
[Code].....
It is getting more and more annoying, everytime i progress the next hurdle is just bigger. The problem is i want to calculate inverse of a matrix but using .inv gives a matrix full of -1.#QNAN values so i decided to write one my self
a function which returns the inverse matrix but something strange happens.
when i debug through the function code it works well and check the matrix that will be returned and the elements are correct.
when the function is called and output matrix is resulted. the element of the matrix is different.
matrix = inversemat(matrx)
inside function, invmat= 3 1 2, 3 5 1, 8 1 2
outside the function matrix = -9.1249e+61 wtf.
here is the code
int main() {
double matrx[3][3]={{1,2,3},{0,1,4},{5,6,0}};
Mat matrx1(3,3,CV_64F,matrx);
Mat inmat;
inmat=inversemat(matrx1);
[Code] ...
invmat elements are correct, as for inmat the elements are too small -9.212412e+61
What is going on, when the matrix is returned.
I am looking for function capable of converting square matrix of integers.Where to find such function? I know the algorythm but have no time to implemnt it.
View 12 Replies View RelatedI need to write a code (in C99). The programe receives an input number (integer) 'n' and then a matrix sized n*n (matrix[n][n]), all numbers are integers. We're supposed to define the matrix's size with malloc. Now the program needs to sort the lines of the matrix (the number in each line), in a single function (!) this way:
even line index (0,2,4,6...): from small to big.
odds line index (1,3,5...): from big to small.
and then print it.
*note: first line is indexed 0, second line is 1, etc.
I was thinking to sort it with bubblesort function with the following if:
if(i%2==1)
do odds sorting.
else
do even sorting.
when i is the index of the row.
my problem is defining the malloc and how do I send the matrix to sorting.If needed I will attach my current (not so good (completly awful)) code and functions as well as an example of what the prog. supposed to do.
I have the following void function devised to assign "+1" or "-1" to each element of a matrix at random. While the function does what I want, when I print the values of the matrix all are set to zero:
#include <vector>
#include "aRand.h"
#include <iostream>
void initConfig(std::vector<std::vector<int> > premat, int nL, int nN) {
int * pnRand;
pnRand = 0;
[Code]...
The function pnRand_plus returns a pointer to an array of random numbers from 1 to 100, with seed time(NULL) + i. The values printed in main are zero, despite the values printed during the function run are fine (-1s and +1s).
how to use bool to identified a identity matrix
View 7 Replies View Relatedi want to know how i can solve this question? do i need to create a class or write the program codes.
View 12 Replies View RelatedI have a matrix that contains zero and nonzero elements. I want to do a function that return 3 arrays.
The first one is for nonzero elements the second array contains the corresponding row numbers of each nonzero element the third array contains the corresponding column numbers of each nonzero element.
I've been trying to get my matrix multiplication program to run a few different ways. My assignments wants me to run it statically using chunks, but we're not supposed to use OpenMPs scheduler. So I'm not sure how that's possible. And secondly, we have to run it dynamically using locks/unlocks.
Static (not sure how to implement chunk)
#pragma omp section
{
printf("Thread %d doing matrix mult", threadID);
if (matrixAcols != matrixBrows) {
cout << "Error, operation not possible" << endl;
[Code]....
The code will run for a long time too. It uses as many threads as we tell it to but it never speeds up the results.
Quote
Thread 2 doing matrix mult
Thread 4 doing matrix mult
Thread 2 doing matrix mult
Thread 4 doing matrix mult
Thread 2 doing matrix mult
Thread 4 doing matrix mult
Thread 2 doing matrix mult
Thread 4 doing matrix mult
Thread 4 doing matrix mult
Thread 4 doing matrix mult
Thread 4 doing matrix mult
Thread 4 doing matrix mult
Thread 4 doing matrix mult
Thread 4 doing matrix mult
I just want to know the code of the program: Write code to accept matrix as aurgument and display its multiplication matrix which return its multiplication matrix.
View 1 Replies View RelatedWhy my function will not return this int. It does make it into the if(... prints "test 32" but will not return the given value(123456789).
#include <iostream>
using namespace std;
int lastZero(int x[]);
int main(){
int myArray[] = {1,1,1};
lastZero(myArray);
[Code] ...
I wanted to return a string I can do
Code:
string parseFilename(string fileName){
return fileName.subtr(/*blah*/);
}
Can I also use pointers/references here though? When would you use a pointer and when just a return statement?
I have a function that needs to return a "uint8_t" value. However before doing the processing I need to perform a test on the argument to check if it's between expected boundaries. Although this function works it gives (a logical) warning that not always a value is returned although expected. What is the normal way for functions like these where I normally should return e.g. -1 in case the test doesn't succeed and otherwise the uint8_t (t) value?
Code:
uint8_t myFunc(int a) {
if (a >= 0 && a <= 100) {
// Perform actions
uint8_t = ...
return t;
}
}
I am trying to return a pointer from a method. Below is a sample of my code.
CSubnode * CTest::GetSubNode() {
return m_psubnode;//this is declared in CTest as CSunbnode * m_psubnode
}
//in another class
m_subnode = m_ptest->GetSubNode(); //m_subnode is declared as a pointer
Is this the correct why to return a pointer?
I need a function to return a string..i need to pass input as "a,b,c,a,c,d,e" function should return out put as "a,b,c,d,e".
View 3 Replies View RelatedI'd like a function to return either a value or the address of that value by the users input. So he can call the function like:
function("adress") - gets an adress, or function("value") - gets the value
I've tried both function overloading and templates, but none of them worked. He might input a character for the address and an int for the value... but...
Another strange thing that i observed is that the value returned by the function below is 0, so the output is address 0.
class testing
{
public:
static int x;
[Code].....
This program that I've made works fine to find midpoint, but not distance. The distancefunction always returns a 1 (true). To try to see that it wasn't the math, I added cout.setf(cout.boolalpha) to see and got a result of "true".
//This program is a start to solve basic coordinatre plane distances and midpoints
#include <iostream>
#include <cstdio>
#include <cstdlib>
using namespace std;
[Code].....
Say I have overloaded functions with different arguments AND return types. Each set of argument has only one corresponding return type.
Code:
Vector grad(Scalar)
Tensor grad(Vector)
Later I have:
Code:
template <class T>
void test(T x) {
... Y = grad(x)
}
Then how do I automatically declare the type of Y. Do I need to make the grad function a template and specialize each of them ?
I used rename function to rename a file.
The file names are in std::string type variable.
The function usage is like this
int result = rename (old_file_name.c_str(),new_file_name.c_str());
I expected result = 0 but i get result = -1.
Does this return code is due to any file pointer holding to this file?
If so what is the reason, and the returning int value indicates wat?
View 4 Replies View RelatedI want to assign a matrix to submatrix of a bigger matrix.
ublas::matrix<int> A(8,5);
ublas::matrix<int> B(2,5);
for(size_t i=0;i<A.size1();++i)
for(size_t j=0;j<A.size2();++j)
A(i,j)=i*A.size2()+j+1;
for(size_t i=0;i<B.size1();++i)
for(size_t j=0;j<B.size2();++j)
B(i,j)=i*B.size2()+j+5;
ublas::matrix_range<ublas::matrix<int> > a(A,ublas::range(0,2),ublas::range(0,5));
a=B;
and it works.
but if the matrix is compressed_matrix type, there's something with it. the error log as below:
Check failed in file boost_1_48_0/boost/numeric/ublas/detail/matrix_assign.hpp at line 1078:
detail::expression_type_check (m, cm)
terminate called after throwing an instance of 'boost::numeric::ublas::external_logic'
what(): external logic
Aborted
I'm not sure this is a bug or not.