array problem

[Cman]

Hi All,

I have a question about 1D arrays.

if I have an array structure like this:

ABCD
EFGH
IJKLM

and I want to create from that, this array:

AABBCCDD
AABBCCDD
EEFFGGHH
EEFFGGHH
IIJJKKLLMM

where the elements, row and columns are doubled?

How do I start? Here's what I did, and its wrong.

                
                numpix = height * width;

                unsigned char* pixdata = new unsigned char[numpix];

	 inFile.read((char *) pixdata, numpix);
     
	
	 for(int i = 0; i < numpix*2; i++)
	 {
	 cout << (unsigned int)pixdata[i] << endl;
	 cout << (unsigned int)pixdata[i] << endl;
	 }

[Edward]

The simplest method would be to dynamically allocate a second array that is twice the size of the base. Then, using two index variables, walk down the base array. For every element in the base array, place two in the modified array. Then increment the base index by one and the modified index by two. Translated into C++, the algorithm is thus.

#include <iostream>

using std::cout;
using std::endl;

int main()
{
    char base[] = "ABCDEFGHIJKLM";
    char *modified = new char[sizeof base * 2 - 1];
    size_t j = 0;

    for (size_t i = 0; base[i] != '\0'; i++, j += 2)
        modified[j] = modified[j + 1] = base[i];
    modified[j] = '\0';
    cout<< modified <<endl;

    delete [] modified;
}

[Cman]

Thank you for your suggestion, will do.

--Cman

[Omnius]

If your compiler complains about size_t, include <cstddef>.