Matematické Fórum

#include <iostream>
#include <fstream>

using namespace std;

// tuto funkci jsem našel na internetu
unsigned char* readBMP(char* filename)
{
    int i;
    FILE* f = fopen(filename, "rb");
    unsigned char info[54];
    fread(info, sizeof(unsigned char), 54, f); // read the 54-byte header
 

    // extract image height and width from header
    int s = *(int*)&info[2];
    int bisize = *(int*)&info[14];
    int width = *(int*)&info[18];
    int height = *(int*)&info[22];    
    int size = 3 * width * height;
    
    unsigned char* data = new unsigned char[size]; // allocate 3 bytes per pixel
    fread(data, sizeof(unsigned char), size, f); // read the rest of the data at once    
    fclose(f);
    for(i = 0; i < size; i += 3)
    {
            unsigned char tmp = data[i];
            data[i] = data[i+2];
            data[i+2] = tmp;
    }

    return data;
}

int main(int argc, char **argv)
{

    unsigned char *data;
    if(argc == 2)
    {
    data = readBMP(argv[1]);
    cout << data; //nic se nevypíše
    }
    else
        return -1;
    
    return 0;
}