Loading data from binary file genereted in C not C#

I have a datafile filled with data generated by ancient program written in plain C. I've managed to load bits of it, but then i noticed i am writing entire struct as sizeof fwrite(struct,sizeof(struct),sizeof(struct)/sizeof(struct),fp);

The struct is
typedef struct {
double value;
double sub_value[9];
}

I am mostly interested in just getting the double value out of it. But how can i do this? Oh right, the struct is used as an array like struct[x][y];

Ideas on how to read data out of the file?

I've used BinaryReader() with readbyte succesfully read data from the file allready. But this struct has got me stuck.

 

Figured it out. You simple iterate thourght it as if it was simple array.