db_sizes_rw.c

#include <stdio.h>
#include <stdlib.h>

struct Sizes {
	int max_data;
	int max_rows;
};

int main(int argc, char** argv) {

	struct Sizes *sizes = (struct Sizes*)malloc(sizeof(struct Sizes));

	sizes->max_rows = 100;
	sizes->max_data = 512;

	FILE *fptr;
	fptr = fopen("file.txt", "w");
	fwrite(sizes, 1, sizeof(sizes), fptr);

	rewind(fptr);
	char c[100];

	if ((fptr = fopen("file.txt", "r")) == NULL) {
 		printf("Error! opening file");
		// Program exits if file pointer returns NULL.
		exit(1);         
	}

	struct Sizes *buff = (struct Sizes*)malloc(sizeof(struct Sizes));

	int rc = fread(buff, sizeof(struct Sizes), 1, fptr);

	printf("Data from the file: %d %d", buff->max_rows, buff->max_data);
	fclose(fptr);

	free(sizes);
	return 0;
}