Thread: Need help on fstream...

I think that if you named your class string it might be illegal because that is likely a keyword since there is an STL string class. Call it something else.

No, it works fine the file is called strang.h/strang.cpp and the class is named String, so that is not the problem. The problem is to find out how many bytes to read/write to/from file, since one member allocates dynamic memory

String classes must reallocate themselves and scan input one character at a time validating it. It should reallocate small blocks of memory such as 20 bytes at a time if it's size is breached. See realloc(...);

String is okay because C++ is case sensitive. Beware of using string or CString.

This is how Im going to use my classes, and whats the problem is about. Sorry if I was unclear on the subject.
In main() I create an array of Customer objects whith the new operator, each of the Customer objects contain members of type String object, which in turn has members of type char*.
Now i want to write and read the array in main to/from file in binary mode, how do I do this?

strang.h
class String
{
private:
char* str;
int len;
........more, but not relevant code here
}

customer.h
class Customer
{
private:
int custNo;
String custName;
.........more, but not relevant code here
}

main_file
void main()
{
Customer* cArray = new Customer[10];
.........more, but not relevant code here
}

Thanks for your kind reply

For C++ steams read a chapter in a textbook. Many people will use fread to read binary data. Open the file in "rb" mode.

FILE *fptr = fopen("filename","rb");
fread(...); //check compiler help

You can also use fgets or fgetc depending on they type of input that you are loading. The best way to load structures is to use fread.

I can't comment on C++ steams. I have not learned them myself.