Passing argument 1 of 'fwrite' makes pointer from integer without a cast?

Question

C++ / C#

Hello. There is an integer type variable with value 7. I am trying to write this variable to a text file with the fwrite() function;

Here is the code:

int size = 7;
FILE *fp;

fp = fopen("saves.txt", "w");
fwrite(size, 1, sizeof(size), fp);
fclose(fp);

But the compiler throws this error:
warning: passing argument 1 of 'fwrite' makes pointer from integer without a cast

What could be the problem?

Answer 1

That you didn't bother to read the description of the fwrite function .
The first parameter must be a pointer to the data being written, the second is the size of a single data element, and the third is the number of these elements.

Answer 2

The fwrite() function writes count objects—each object is size characters long—to the stream specified by stream from the character array specified by buf. That is, instead of size, you must pass a pointer to the buffer, from where fwrite will copy the characters to the file.

Answer 3

man fwrite
You are trying to read data from area 0x7, which is of course wrong. It is necessary to transfer the pointer to the area as the first parameter. And in general, you have some kind of porridge in the parameters.
fwrite(&size, sizeof(size), 1, fp);