Problem with reading and writing to binary file in C++
- by Reem
I need to make a file that contains "name" which is a string -array of char- and "data" which is array of bytes -array of char in C++- but the first problem I faced is how to separate the "name" from the "data"? newline character could work in this case (assuming that I don't have "\n" in the name) but I could have special characters in the "data" part so there's no way to know when it ends so I'm putting an int value in the file before the data which has the size of the "data"!
I tried to do this with code as follow:
if((fp = fopen("file.bin","wb")) == NULL)
{
return false;
}
char buffer[] = "first data\n";
fwrite( buffer ,1,sizeof(buffer),fp );
int number[1];
number[0]=10;
fwrite( number ,1,1, fp );
char data[] = "1234567890";
fwrite( data , 1, number[0], fp );
fclose(fp);
but I didn't know if the "int" part was right, so I tried many other codes including this one:
char buffer[] = "first data\n";
fwrite( buffer ,1,sizeof(buffer),fp );
int size=10;
fwrite( &size ,sizeof size,1, fp );
char data[] = "1234567890";
fwrite( data , 1, number[0], fp );
I see 4 "NULL" characters in the file when I open it instead of seeing an integer. Is that normal?
The other problem I'm facing is reading that again from the file! The code I tried to read didn't work at all :( I tried it with "fread" but I'm not sure if I should use "fseek" with it or it just read the other character after it.
Forgive me but I'm a beginner :(
