Writing in a binary file - c

Question

My program scans names and birth years and stores them in an array of structures. Scanning from keyboard and printing in screen works fine, but I'm not sure whether printing in my binary file is correct because my program runs without errors and I can't check if the data has been printed correctly in the binary file.
My question is about whether the syntax of my "fwrite" functions is correct.
#include <stdio.h>
#define MAXNAME 50 //size of name
#define MAXPERSONS 2 //Max num of persons
typedef struct{
char name[MAXNAME];
int year;
}person_t;
int read_person(person_t[], int);//scans the person
int write_person(const person_t[], int, FILE*);//prints the persons in the screen and the bfile
int main()
{
FILE *pfile;
person_t v[3];
int iscan=0,iprint;
if((pfile=fopen("persons.bin","wb"))==NULL) printf("couldnt open<vehicles.txt>\n");
else{
while(iscan<MAXPERSONS){
read_person(&v[iscan],iscan+1);
iscan++;
}
for(iprint=0;iprint<iscan;iprint++)
write_person(&v[iprint],iprint+1,pfile);
}
fclose(pfile);
printf("\n\n");
return 0;
}
int read_person(person_t v[],int i)
{
printf("Person %d",i);
printf("\n\tName: ");
fflush(stdin);
gets(v->name);
printf("\n\tYear: ");
scanf("%d",&v->year);
}
int write_person(const person_t v[],int j, FILE *pfile)
{
//print in screen
printf("\nPerson %d",j);
printf("\n\tName: %s\n",v->name);
printf("\n\tYear: %d\n",v->year);
//print in the binary file
fwrite(v->name,sizeof(char),1,pfile);
fwrite(&v->year,sizeof(int),1,pfile);
}
This program reads from the bin file
#include<stdio.h>
#define MAXNAME 50 //size of name
#define MAXPERSONS 2 //Max num of persons
typedef struct{
char name[MAXNAME];
int year;
}person_t;
int read_person(person_t[], int, FILE*);
int write_person(const person_t[], int);
int main(){
FILE *pfile;
person_t v[3];
int iscan=0,iprint;
if((pfile=fopen("persons.bin","rb"))==NULL) printf("couldnt open<vehicles.txt>\n");
else{
while(iscan<MAXPERSONS){
read_person(&v[iscan],iscan+1,pfile);
iscan++;
}
for(iprint=0;iprint<iscan;iprint++)
write_person(&v[iprint],iprint+1);
}
fclose(pfile);
printf("\n\n");
return 0;
}
int read_person(person_t v[],int i, FILE *pfile){
//read from the binary file
fread(v->name, sizeof(v->name),1,pfile);
fread(&v->year,sizeof(v->year),1,pfile);
}
int write_person(const person_t v[],int j){
//print in screen
printf("\nPerson %d",j);
printf("\n\tName: %s\n",v->name);
printf("\n\tYear: %d\n",v->year);
}

Answer 1

Suggest changing fwite() to write the full size of person_t.
int write_person(const person_t v[], int j, FILE *pfile) {
//print in screen
printf("\nPerson %d",j);
printf("\n\tName: %s\n",v[j].name);
printf("\n\tYear: %d\n",v[j].year);
//print in the binary file
if (1 != fwrite(&v[j], sizeof(v[j]),1, pfile)) handle_error();
return 0;
}
int read_person(person_t v[], int i) {
printf("Person %d",i);
printf("\n\tName: ");
// don't do this fflush(stdin);
// consider scanf() gets(v.name);
// " %49[^\n]": space to consume leading whitespace, 49 (50 -1 ) limit input, [^\n] to read any text but \n
if (1 != scanf(" %49[\n]", v[i].name)) handle_error();
printf("\n\tYear: ");
if (1 != scanf("%d",&v[i].year)) handle_error();
return 0;
}

Answer 2

You might consider writing and reading the entire person_t struct.
int write_person(const person_t v[],int j, FILE *pfile)
{
//print in screen
printf("\nPerson %d",j);
printf("\n\tName: %s\n",v[j].name);
printf("\n\tYear: %d\n",v[j].year);
fwrite(&(v[j]),sizeof(person_t),1,pfile);
}
The general idea you are approaching is called 'serialization' or 'marshalling' (depending upon author). There are many ways serialize or marshall data, but some good approaches are JSON, UBJSON, MessagePack, and ProtocolBuffers, among others.