C++ save vector or float to bin

void save_bin(std::vector<float> &data_vector, std::string name = "mnn.bin")
{                                                                                 
    std::ofstream outFile(name, std::ios::out | std::ios::binary);                
    int size = int(data_vector.size());                                           
    outFile.write((char *)data_vector.data(), sizeof(float) * size);              
    outFile.close();                                                              
} 

int write_bin_to_file(const char* file_path, char* buf, int size_buf )
{    
    FILE * fid = fopen(file_path ,"wb");
    for(int i = 0 ; i < size_buf; i ++)
    {
        fwrite(&buf[i],sizeof(char),1,fid);
    }
    fclose(fid);
   return 0;
}