Home c++ Write a dynamic array in a binary file C++

Write a dynamic array in a binary file C++




Trying to function, which will create a BMP file.

The basic structure:

# pragma pack (push, 1)
  TypeDef struct {
    int16_t bfType;
    uint32_t bfSize;
    int16_t bfReserved1;
    int16_t bfReserved2;
    uint32_t bfOffBits;
#pragma pack (pop)
#pragma pack (push, 1)
  TypeDef struct {
    uint32_t biSize;
    int32_t biWidth;
    int32_t biHeight;
    int16_t biPlanes;
    int16_t biBitCount;
    uint32_t biCompression;
    uint32_t biSizeImage;
    int32_t biXPelsPerMeter;
    int32_t biYPelsPerMeter;
    uint32_t biClrUsed;
    uint32_t biClrImportant;
#pragma pack (pop)
#pragma pack (push, 1)
  TypeDef struct {
    int8_t rgbBlue;
    int8_t rgbGreen;
    int8_t rgbRed;
    int8_t rgbAplha;
#pragma pack (pop)

Sami variables and functions:

RGBQUAD * palette;
void Create (const char * fname) {
  ofstream out (fname, ios :: binary);
  palette = new RGBQUAD [16];
  // Here missed filling palette write, but filled to the test here so = new RGBQUAD [16] {{255,255,255,0}, {}};
  bfh = {};
  bih = {};
  bfh.bfType = 0x4d42;
  out.write ((const char *) & amp; bfh, sizeof (bfh));
  out.write ((const char *) & amp; bih, sizeof (bih));
  // Here I have tried a lot of options, but none of them worked.

As written in binary palette? If you make it a static array and write

out.write ((const char *) & amp; test, sizeof (test));

everything will work perfectly, but still need a dynamic array. Please tell me how to realize, what I need for understanding will be glad if you explain how it works.

Here is an example:

palette = new RGBQUAD [16] {
    {0,0,0,0}, {0, 128,0,0}, {0, 0, 128, 0}, {} 0,128,128,0,
    0,0,0,128 {}, {} 0,128,0,128, 0,0,128,128 {}, {} 0,128,128,128,
    0,192,192,192 {}, {} 0,255,0,0, 0,0,255,0 {}, {} 0,255,255,0,
    0,0,0,255 {}, {} 0,255,0,255, 0,0,255,255 {}, {0, 255, 255, 255}
out.write ((const char *) palette, sizeof (RGBQUAD) * 16);

But what happens (sorry for the quality):

Obviously, this is not what I expected to see.

I looked up and it turns out that the palette is initialized not like I have and all the elements are equal to -51. I do not know yet what was going on.

Answer 1, Authority 100%

The problem is not in the record, and initialize an array of structures using c initializer list, and it’s interesting, because I just thought that this design should work ..

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