使用 ifstream 从二进制文件中读取 4 个字节

Question

I have a binary file that contains floats so that every 4 bytes are a float. I'm not sure how I can read in a way that every four bytes would be stored as a float so I can do whatever I need with it.

Here's my code:

int main()
{
    float i;
    std::ifstream inFile("bin_file", std::ios::binary);
    while (inFile >> i)
    {
        std::cout << i;
    }
    inFile.close();
    return 0;
}

In that case, it won't even enter the while loop unless I define i as a char. I guess that's because it reads 1 byte every time and can't store it as a float. Btw I've checked and the file opens.

Thanks!

Answer 1

The operator>> in streams is designed for formatted data (ie strings). You want to use read instead:

int main()
{
    float i;
    std::ifstream inFile("bin_file", std::ios::binary);
    while(inFile.read(reinterpret_cast<char*>(&i), sizeof(i))) {
        std::cout << i;
    }
    inFile.close();
    return 0;
}