string in structure and fread()

[Mohsen Pahlevanzadeh <mohsen@xxxxxxxxxxxxxxxxx>]

Dear all,
I have a program that it should write a struct in binary file.My struct
is here:
///////////////////
struct book{
    string name;
	string author;
	string publisher;
	string translator;
	bool translation;
	bool stock;
};
////////////////////////
Then i wrote the following function that write to file:
////////////////////////////
void WriteFile::addNode(string name, string publisher, string author,
bool stock,string translator , bool translation ){
	book * tmp = new book;
	int line = 1;
	short unsigned i;
	string memory;

	short unsigned size = 100 - strlen((const char *)name.data());
	memory = '`';
	for (i =0 ;i<size;i++)
		memory += '`';
	tmp->name = name  + memory;

	size = 100 - strlen((const char *)publisher.data());
	memory = '`';
	for (i =0 ;i<size;i++)
		memory += '`';
	tmp->publisher =  publisher  + memory;

	size = 100 - strlen((const char *)author.data());
	memory = '`';
	for (i =0 ;i<size;i++)
		memory += '`';
	tmp->author = author  + memory;


	size = 100 - strlen((const char *)translator.data());
	memory = '`';
	for (i =0 ;i<size;i++)
		memory += '`';
	tmp->translator = translator + memory;

	tmp->stock = stock;
	tmp->translation = translation;

	fseek(bookFilePtr,0L,SEEK_END);
	fwrite(ptr,408,1,bookFilePtr);


///////////////////////////
Note that i wanted to use fixed length of each field, So, for example
if a field has 30 character, i fill 71 character "`" at end of field. 30
+71= 101
So 4*string*101+2*bool*4=408 = length of struct.

Then i wrote the following function to  read all of records:

///////////////////////////////////////////////
void ReadFile::printList(){
	fseek(bookFilePtr,0L,SEEK_SET); // set to begin of file


	int counter = 1;
	long int line = 1;
	int pageCounter = 1;


	while ( fread(bookPtrObj,408,1,bookFilePtr) == 1 ){
		string output;
		mvprintw(++line, 27,"***Title*****************Value*********" );
		output = "Name:               " + bookPtrObj->name;
		mvprintw(++line, 27, output.data());

		output = "Publisher:          " + bookPtrObj->publisher;
		mvprintw(++line, 27,output.data());

		output = "Author:             " + bookPtrObj->author;
		mvprintw(++line, 27,output.data());

		output = "Translator:         " + bookPtrObj->translator;
		if (bookPtrObj->translation == true )
			mvprintw(++line, 27,output.data());

		if (bookPtrObj->stock != true )
			mvprintw(++line, 27,"Stock:              The given book doesn't
exist.");
		else
			mvprintw(++line, 27,"Stock:              The given book exist.");

		if ( pageCounter % 3 == 0){
			mvprintw(++line, 27,"Press any key to see next page...");
			getch();
			clear();
			line = 1;

		}
		pageCounter++;
		refresh();

		fseek(bookFilePtr, counter * sizeof(struct book) ,SEEK_SET); // seek
to next data
		counter ++;
	}
}

///////////////////////////////////////////////

But i get the segmentation fault on read each field.
Because i didn't specify length of each field in read.How i specify
length of each field in reading?

--mohsen

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