Reading an integer size element from file

Question

Hello, I need some help for reading an integer size element from a file. In C++ there is the function fread with the following signature size_t fread(void ptr, size_t size, size_t nitems, FILE stream); where size is the size of one of the elements. Using this function in c++, you can read an integer by setting size = sizeof(int). I need this function because I am writing in a file a lot of integers and characters without any separator and I need to take the first element which is always an integer. Here is an example:
I have: int x = 234; String y = "12ABC". I write those two elements in an output file. Now, when reading from that file the content of the file is: 23412ABC and I need to take the two elements x and y.
Can anyone help ?

Answer 1

I see what you mean but the problem is a bit more complicated, maybe I did not explain well. I need to copy data in a text file and retrieve them. Most data that will be written in the file are stored in an char array. those data may contain digits, letters, special characters... depending on their ASCII code. But before writting that char array, I need to write an integer corresponding to a specific index and I have no way of predicting the number of digits of that integer. So for example, my char array contains the following data: {'1','2','3','a','b','c'} and my int equals 10000. Using FileWriter I write the int and then the char array using the method myfile.write with its arguments. Next step, I want now to read from myfile.txt the data that I wrote in the first step. I start reading the int then using myfile.read(mychararray, 0, 6) /*6 being the size of the bloc to be read*/ I read the remaining characters and store each char in a cell of mychararray. The problem with this, is that using the method .read I can not read the first integer since I don't know its size: it may contain 1, 2 or even more digits.
I know that storing everything in bytes would make my task easier, but I necessarily need to store an array of characters and then use .read method to store the content of the file (after having read the int of course) in a char array. Last clarification, the step of writing int then char array is reproduced n times before calling myfile.close();
I hope it is clearer than before. Any suggestion for this problem would be welcome.