Data structure and patients records - c

Question

Computerizing health records could make it easier for the patients to share their health profiles and histories among their various health care professionals. A health clinic needs your help to computerize the patients' health records. The patient's records consist of first name, middle name, last name (including SR. JR., etc), gender, date of birth, height (in inches), weight (in pounds). The clinic requires the following features of the program:
read existing record from a file where each patient record is one line entry separating each data with comma
add additional records to file
a function to calculate and return patients age in 3yrs
a function that calculates body mass index with the given formula BMI=(weight-in-pounds X 703)/(height-in-inches X 2) or BMI = (weight-in-kgs)/(height-in-meters X 2)
search patient's name and display patient's information with age and BMI value including category
update patient's information on date of birth, height and/or weight and save updates to file
display all records in tabular format
So far what I have made is:
#include<stdio.h>
#include<stdlib.h>
main(){
FILE*fin;
char name,fname,mname,lname,ename,gender,ch,getch,patient;
int dob,month,day,year,height,weight;
fin=fopen("oldrec.c","w");{
printf("Error: File does not exists");
return 0;
}
{
printf("Add Record? y/n");
ch=toupper(getch);
if(ch='y')
break;
}while (1);
struct patient{
char name;
char fname[20];
char mname[20];
char lname[20];
char gender;
int dob;
int month;
int day;
int year;
int height;
int weight;
printf("/n Patient's Name");
printf("First Name: ");
scanf("%s", &patient.fname);
printf("Middle Name: ");
scanf("%s", &patient.mname);
printf("Last Name: ");
scanf("%s", &patient.lname);
printf("Gender: ");
scanf("%s", &patient.gender);
printf("Date of Birth");
printf("Month: ");
scanf("&d", &patient.month);
printf("Day: ");
scanf("&d", &patient.day);
printf("Year: ");
scanf("%s", %patient.year);
printf("Height: ");
scanf("%d", & patient.height);
printf("Weight: ");
scanf("%d", &patient.weight);
}
I have made another file already, but when I run the codes, it says "Error: File does not exist". What is wrong, and what are the codes for the other problems? Please help me! This is our final requirement on my data structure subject.

Answer 1

fin=fopen("oldrec.c","w");{ // no if
printf("Error: File does not exists"); // all statements will be executed
return 0; // and function will terminate here
}
Ofcourse it will show that message , no condition . No matter if fopen is successful without if all statements will be executed.
Put it in a if block witn a condition .
Write like this -
fin=fopen("oldrec.c","w");
if(fin==NULL){ // check if fin is NULL
printf("Error: File does not exists");
return 0;
}
Other problems are these statements -
scanf("%s", &patient.fname);
...
scanf("%s", &patient.mname);
...
scanf("%s", &patient.lname);
...
scanf("%s", &patient.gender); // use %c for reading char variable
...
scanf("%s", %patient.year); // use %d to read int
^ whats this
Write these statemetns like this -
scanf("%s", patient.fname);
...
scanf("%s", patient.mname);
...
scanf("%s", patient.lname);
...
scanf("%c", &patient.gender);
...
scanf("%d", &patient.year);