write struct to file

[john tindell]

hey im trying to store data in a file from a struct? can anyone point me to how i should go about doing this, i tried like this but it says that cant convert my struct to char *

struct user_data{
	char username[25];
	char password[25];
};

......

ofstream file(USER_DATA,ios::out|ios::binary);
file.write(ud,sizeof(ud));
file.close();

can someone please point me on how i should do this thanks.

[sw_is_great]

u can do a memcpy to a character array.

[parksie]

file.write((char*)&ud, sizeof(ud));

Need to pass the address of the struct, not the struct itself.

Watch for structure padding when you write it (for example, it may write more than 50 bytes).

[john tindell]

cheers, could i do the same if i wanted to read the file into a struct?

[wey97]

ifstream in(USER_DATA, ios::in | ios::binary);
in.read((char*)&ud, sizeof(ud));
in.close();

[wey97]

FYI:
If you look at the file with a text editor you can't read the text but
if you open it with a binary editor you can understand it.

You may want to look at encrypting the output if you don't want it
to easily be read.