讀取.bmp文件c ++，值錯誤？

Question

這是我的代碼，用於從bmp文件讀取（使用windows.h）。 它從BITMAPFILEHEADER讀取正確的值，但是從BITMAPINFOHEADER讀取的所有值都是40（十六進制為28）。 怎么了？

ifstream file("d3.bmp",ios::binary);
BITMAPFILEHEADER fheader;
BITMAPINFOHEADER aImg;

ofstream fileOut("newfile5.txt",ios::app);

file.read((char*)&fheader.bfType, sizeof(WORD));
fileOut<<std::hex<<fheader.bfType<<"\n";
file.read((char*)&fheader.bfSize, sizeof(DWORD));
fileOut<<fheader.bfSize<<"\n";
file.read((char*)&fheader.bfReserved1, sizeof(WORD));
fileOut<<fheader.bfReserved1<<"\n";
file.read((char*)&fheader.bfReserved2, sizeof(WORD));
fileOut<<fheader.bfReserved2<<"\n";
file.read((char*)&fheader.bfOffBits, sizeof(DWORD));
fileOut<<fheader.bfOffBits<<"\n";


file.read((char*)&aImg.biSize,sizeof(DWORD));
fileOut<<aImg.biSize<<"\n";
file.read((char*)&aImg.biWidth, sizeof(LONG));
fileOut<<aImg.biSize<<"\n";
file.read((char*)&aImg.biHeight, sizeof(LONG));
fileOut<<aImg.biSize<<"\n";
file.read((char*)&aImg.biPlanes, sizeof(WORD));
fileOut<<aImg.biSize<<"\n";
file.read((char*)&aImg.biBitCount, sizeof(WORD));
fileOut<<aImg.biSize<<"\n";
file.read((char*)&aImg.biCompression, sizeof(DWORD));
fileOut<<aImg.biSize<<"\n";
file.read((char*)&aImg.biSizeImage, sizeof(DWORD));
fileOut<<aImg.biSize<<"\n";
file.read((char*)&aImg.biXPelsPerMeter, sizeof(LONG));
fileOut<<aImg.biSize<<"\n";
file.read((char*)&aImg.biYPelsPerMeter, sizeof(LONG));
fileOut<<aImg.biSize<<"\n";
file.read((char*)&aImg.biClrUsed, sizeof(DWORD));
fileOut<<aImg.biSize<<"\n";
file.read((char*)&aImg.biClrImportant, sizeof(DWORD));
fileOut<<aImg.biSize<<"\n";

Answer 1

我敢打賭，正在讀取的值是正確的，只是您總是一遍又一遍地輸出相同的字節：

file.read((char*)&aImg.biSize,sizeof(DWORD));
fileOut<<aImg.biSize<<"\n"; //ok, biSize
file.read((char*)&aImg.biWidth, sizeof(LONG));
fileOut<<aImg.biSize<<"\n"; //wait, biSize again?
file.read((char*)&aImg.biHeight, sizeof(LONG));
fileOut<<aImg.biSize<<"\n"; //well somehow I'm getting suspicious
file.read((char*)&aImg.biPlanes, sizeof(WORD));
fileOut<<aImg.biSize<<"\n"; //...
file.read((char*)&aImg.biBitCount, sizeof(WORD));
...