Trying to save a struct into a file - c

Question

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
struct data {
char *first;
char *last;
char *email;
int age;
struct data *next;
};
typedef struct data dat;
dat family;
dat family_array[4];
char array[100];
void menu(){
printf("\n1. Father\n");
printf("2. Mpther\n");
printf("3. Son 1\n");
printf("4. Son 2\n");
}
int mode_select(){
int x;
printf("\nMake your choice:");
scanf("%d" ,&x);
return x;
}
Opens file and returns its address
FILE* load_read(){
FILE *fp;
fp=fopen("Family Data.dat" , "rb");
return fp;
}
FILE* write(){
FILE *fp;
fp=fopen("Family Data.dat" , "wb");
return fp;
}
Reads data for struct
dat new_data( const char *first , const char *last , const char *email , int age){
printf("\nGive first name: ");
scanf("%s" , array );
first=(char*)malloc((strlen(array)+1)*sizeof(char));
strcpy( &(family.first), array);
printf("\nGive last name: ");
scanf("%s" , array);
last=(char*)malloc((strlen(array)+1)*sizeof(char));
strcpy(&(family.last), array);
printf("\nGive email address: ");
scanf("%s" , array);
email=(char*)malloc((strlen(array)+1)*sizeof(char));
strcpy(&(family.email) , array);
printf("\nGive age: ");
scanf("%d" , &(family.age));
return family;
}
Saves data from struct to file
void save_to_file(FILE *fp , dat x){
fprintf(fp , "Dataaa:\n ");
fprintf(fp ,"Name: %s %s\n" , x.first , x.last);
fprintf(fp , "Email: %s\n" , x.email);
fprintf(fp , "Age: %d\n" , x.age);
}
Saves data to an array
void save(x){
family_array[x-1]=new_data(family.first , family.last , family.email , family.age);
}
Main fuction
int main(){
int x ,i;
FILE *fp;
for(i=0;i<4;i++){
mode();
x=mode_select();
fp=write();
save(x);
save_to_file(fp , family_array[i]);
}
fclose(fp);
return 0;
}
The programm crashes when its time to save data to file with save_to_file fuction!
Thank you very much for your help!

Answer 1

Your family.first, family.last and family.email pointer are never initialized, but you write to them using strcpy in new_data
It's not clear what you are trying to do with the arguments of new_data, and why you never use their value but replace it by a newly allocated buffer, which you never write to and never free

Answer 2

The new_data function is an unreadable mess, as well as being wrong. It already returns all the information that it reads via its return value, so it does not need any parameters.
The right way is:
dat new_data(void)
{
dat item = { 0 };
char array[100]; // does not need to be global
printf("Give first name: ");
if ( 1 != scanf("%99s", array ) )
exit(EXIT_FAILURE);
item.first = malloc( strlen(array) + 1 );
strcpy(item.first, array);
// same for other items....
return item;
}
and the code in save would be:
family_array[x-1] = new_data();
Your object family is not required either.
If you want to make new_data() be able to recover from errors by doing something other than exit then you will need to return a success/failure indication. (and include extra code for freeing memory).
Note that the POSIX functions strdup and/or getline would make this code a bit simpler.