如何有效地将二进制文件读入矢量C ++

Question

I need to read a large binary file (~1GB) into a std::vector<double> . I'm currently using infile.read to copy the whole thing into a char * buffer (shown below) and I currently plan to convert the whole thing into doubles with reinterpret_cast . surely there must be a way to just put the doubles straight into the vector ?

I'm also not sure about the format of the binary file, the data was produced in python so it's probably all floats

ifstream infile(filename, std--ifstream--binary);

infile.seekg(0, infile.end);     //N is the total number of doubles
N = infile.tellg();              
infile.seekg(0, infile.beg);

char * buffer = new char[N];

infile.read(buffer, N);

Answer 1

Assuming the entire file is double, otherwise this wont work properly.

std::vector<double> buf(N / sizeof(double));// reserve space for N/8 doubles
infile.read(reinterpret_cast<char*>(buf.data()), buf.size()*sizeof(double)); // or &buf[0] for C++98