Error when trying to join vectors

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Error when trying to join vectors

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#1 by (2 votes)
#2 by (0 votes)

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I want to join the vectors vector1 and vector2 into a single vector vectorUnion

#include<iostream>
using namespace std;
void muestraVector(int v[], int longitud);
void unionVectores(int vector1[], int longit1, int vector2[], int longit2, 
int vectorUnion[],int longit3);
int main() {

const int MAXIMOV = 5;
const int MAXIMOV1 = 5;
const int MAXIMOV2 = 6;
const int O = 11;

int vector1[MAXIMOV][MAXIMOV1] = { { 1, 3, 5, 6, 9 },{ 1, 2, 3, 4, 5 },{ 7, 8, 9, 10, 11 },{ 1, 3, 5, 7, 9 },{ 10,17,25,29,32 } };
int vector2[MAXIMOV][MAXIMOV2] = { { 2, 4, 6, 7, 8, 13 },{ 6, 7, 8, 9, 10, 11 },{ 1, 2, 3, 4, 5, 6 },{ 2, 4, 6, 8, 10, 12 },{ 1,4,6,45,46,47 } };

int vectorUnion[MAXIMOV][O];

for (int v = 0; v < MAXIMOV; v++)
{
    cout << "VECTOR1" << endl;
    muestraVector(vector1[v], MAXIMOV1);
    cout << "VECTOR2" << endl;
    muestraVector(vector2[v], MAXIMOV2);
    cout << "Union de los vectores : " << endl;
        unionVectores(vector1[v], MAXIMOV1, vector2[v], MAXIMOV2, 
vectorUnion[v], O);
        muestraVector(vectorUnion[v], O);

}

system("pause");


return 0;
}

void muestraVector(int v[], int longitud)
{
cout << "[";
if (longitud > 0)
{
    cout << v[0];
}
for (int i = 1; i < longitud; i++)
    cout << "," << v[i];
cout << "]" << endl;
}

void unionVectores(int vector1[], int longit1, int vector2[], int longit2, 
int vectorUnion[],int longit3) {

int x = 0;
int z = 0;
for (int i = 0; i < (longit1 + longit2); i+2) {

    vectorUnion[i] = vector1[x];  
    x++;
}
for (int j = 1; j < (longit1 + longit2); j + 2) {

    vectorUnion[j] = vector2[z];
    z++;
}
}

Then I thought about doing a function that would allow me to join the two vectors so that if for example

vector1 : {1,3,5,6,9}
vector2 : {2,4,6,7,8,13}

the united vector would be:

{1,2,3,4,5,6,6,7,8,9,13}

but you send me an error when I try to change the value of

vectorUnion[i] = vector1[x]  // se produjo una excepción:infracción de acceso de lectura.

I guess this can not be done, but I do not know why you can not, could you guide me?

c++ array

asked by Chariot 23.02.2018 в 20:25

source

2 answers

0

Since you are working with 1 formations of known size at compile time, I would advise you to use template functions to perform the copy, a join vector function could look like this:

template <typename tipo, std::size_t tamanyo_a, std::size_t tamanyo_b>
void unir_vectores(tipo (&vector_a)[tamanyo_a], tipo (&vector_b)[tamanyo_b], tipo (&destino)[tamanyo_a + tamanyo_b])
{
    auto iterador = std::copy(std::begin(vector_a), std::end(vector_a), std::begin(destino));
    std::copy(std::begin(vector_b), std::end(vector_b), iterador);
}

The advantage of this approach is that it obtains the size of the 1 formations at compile time and checks that the type matches before joining and will not allow you to join two formations 1 on a third that does not match the size of the sum of the size of the previous two, for example, this would fail:

int a[10]{}, b[11]{}, c[12]{};
unir_vectores(a, b, c); // Error, espera que c tenga tamanyo 21

You can see the code working in Wandbox 三へ (へ ਊ) へハッハッ .

Also known as arrays or in English: arrays.

answered by 25.02.2018 в 00:26

Two columns with the same name Search for consecutive characters in a PHP string

score 2 · Accepted Answer

In this loop:

for (int i = 0; i < (longit1 + longit2); i+2) {
  vectorUnion[i] = vector1[x];  
  x++;
}

We have that both i and x will move in the range (0,10). vectorUnion[i] is not going to give you problems because vectorUnion admits 11 integers, but vector1 is a vector of only 5 elements and that implies that this loop performs 6 readings out of the memory of vector1 .

With the preceding loop, exactly the same thing happens and modern Operating Systems have the bad habit of preventing a process from accessing memory that does not belong to it, that is why it prevents the corruption of the memory of other applications and the way it has to prevent this from happening is killing the process that accesses the memory ... in this case your application.

The solution is as simple as rearranging those loops:

The first loop can only iterate in the range 0..4
The second loop will iterate in the range 0..5.
The index to vectorUnion must be shared by both loops:

Something like this:

int i;
for(i=0; i<longit1; ++i )
  vectorUnion[i] = vector1[i];

for(int x=0; x<longit2; ++x, ++i )
  vectorUnion[i] = vector2[x];

Or, if you prefer with pointers:

int* ptr = vectorUnion;
for(int i=0; i<longit1; ++i, ++ptr )
  *ptr = vector1[i];

for(int i=0; i<longit2; ++i, ++ptr )
  *ptr = vector2[i];