write()

#include < iostream >
#include < fstream >
#include < cstring >
using namespace std;

int main()
{
    ofstream out("test", ios::out||ios::binary);
    
    if(!out) {
        cout << "can not open output file\n";
        return 1;
    }
    
    double num = 100.45;
    char str[] = "this is a test";
    
    out.write((char *) &num, sizeof(double));
    out.write(str, strlen(str));
    
    out.close();
    
    return 0;
}