cpp 二进制文件读写

// reading binary file
    #include <iostream>
    #include <fstream.h>
    
    const char * filename = "test.txt";
    
    int main () {
        char * buffer;
        long size;
        ifstream in (filename, ios::in|ios::binary|ios::ate);
        size = in.tellg();
        in.seekg (0, ios::beg);
        buffer = new char [size];
        in.read (buffer, size);
        in.close();
        
        cout << "the complete file is in a buffer";
        
        delete[] buffer;
        return 0;
    }
    //运行结果：
    The complete file is in a buffer

void file3D::open(string filename) 
{
    ifstream fcin;
    fcin.open(filename, ios::binary);　　　　//　指明文件打开的方式
    if (!fcin) {
        cout << "file " << filename << " is not exist!" << endl;
    }

    fcin.seekg(82*sizeof(float), ios::beg);    //指明初始文件指针偏移地址

    for (int i = 0; i <= 20; ++i) {
        float tmp;
        fcin.read((char *)&tmp, sizeof(float));       //使用重载的read（）函数
        cout << "number " << i << " is:  " << tmp << endl;
    }

    fcin.close();
}