Editing existing file in C

Question

I am trying to make this simple hospital management system for my school project in C, when i try to edit the existing patient details by searching with their id number, That patient information gets edited, patient id,name etc but the problem is all other patients information that i don't want to edit becomes blank(means in place of id it becomes 0 and other remains blank except the edited patients details).

How do i edit only the details of patient i want to edit??

My code for editing

fp is my original filename and temp is temporary file i have created

    #include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include<process.h>
typedef struct Hospital{
  int patientId;
  char fname[20];
  char lname[20];
  char gender[10];
  int age;
  char ReferredTo[30];
}Hospital;
Hospital hospi;
void Record();
void Display();
void Add();
void Edit();
void Search();
void Delete();
int main(){
    int ch;
    top:
    printf("\n1.Create Record of patients");
    printf("\n2.Display Record of patients");
    printf("\n3.Append Record of Additional patients");
    printf("\n4.Edit the record of the patients");
    printf("\n5.Search record of the patients");
    printf("\n6.Delete record of the patients");
    printf("\n---------------------------------------");
    printf("\nEnter your choice: ");
    scanf("%d",&ch);
    printf("\n---------------------------------------");

if(ch == 1){
  Record();
}else if(ch == 2){
  Display();
} else if(ch == 3){
  Add();
  //goto top;
}else if(ch == 4){
  Edit();
}else if(ch == 5){
  Search();
}else if(ch == 6){
  Delete();
}else{
  printf("Invalid Choice");
  }
}

void Record(){
  FILE *fp;
  int n = 0,i;
  fp = fopen("C:\\project\\record.txt","w");
  if(fp == NULL){
    printf("Couldn't Open the file");
  }else{
    printf("\nHow many Record You want to enter: ");
    scanf("%d",&n);
    for(i=0; i<n; i++){
      printf("\nEnter Patient ID: ");
      scanf("%d",&hospi.patientId);
      printf("\nEnter  Patient First Name: ");
      scanf("%s",hospi.fname);
      fflush(stdin);
      printf("\nEnter Patient Last Name: ");
      scanf("%s",hospi.lname);
      printf("\nEnter Patient sex(M for male F for Female): ");
      scanf("%s",hospi.gender);
      printf("\nEnter Patient Age: ");
      scanf("%d",&hospi.age);
      printf("\nEnter the Doctor Name which the patients is refered to: ");
      scanf("%s",hospi.ReferredTo);
      fwrite(&hospi,sizeof(hospi),1,fp);
    }
    printf("\nData Successfully Recorded....:)");
  }
  fclose(fp);
}

void Display(){
  FILE *fp;
  fp = fopen("C:\\project\\record.txt","r");
  if(fp == NULL){
    printf("Error: can't open file");
  }else{
    while(fread(&hospi,sizeof(hospi),1,fp)==1){
      printf("\nPatient Id = %d\n",hospi.patientId);
      printf("Patient Fullname = %s %s\n",hospi.fname,hospi.lname);
      fflush(stdin);
      printf("Patient Gender: %s\n",hospi.gender);
      printf("Patient Age = %d\n",hospi.age);
      printf("Referred Doctorr = %s\n",hospi.ReferredTo);
      printf("---------------------------------------\n");
    }
  }
  fclose(fp);
}

void Add(){
  FILE *fp;
  char ch;
  int n = 0,i;
  fp = fopen("C:\\project\\record.txt","a");
  if(fp == NULL){
    printf("Error: can't open file");
  }else{
    //printf("\nHow many Additional patients you want to add: ");
    //scanf("%d",&n);
      printf("\nEnter Patient ID: ");
      scanf("%d",&hospi.patientId);
      printf("\nEnter Patient First Name: ");
      scanf("%s",hospi.fname);
      fflush(stdin);
      printf("\nEnter Patient Last Name: ");
      scanf("%s",hospi.lname);
      printf("\nEnter Patient sex(M for male F for Female): ");
      scanf("%s",hospi.gender);
      printf("\nEnter Patient Age: ");
      scanf("%d",&hospi.age);
      printf("\nEnter the Doctor Name which the patients is refered to: ");
      scanf("%s",hospi.ReferredTo);
      fwrite(&hospi,sizeof(hospi),1,fp);
    }
      printf("\nDo you want to continue adding data press('y' for yes and 'N' for no ) ");
      scanf("%s",ch);
      while(ch =='y'){
           Add();
      }
      fclose(fp);
}

void Edit(){
  int Pid;
  FILE *fp,*temp;
  fp = fopen("C:\\project\\record.txt","r");
  temp = fopen("C:\\project\\temp.txt","a");
  Hospital hospt;
  printf("\nEnter the patient ID you want to Edit the data: ");
  scanf("%d",&Pid);
  while(fread(&hospt,sizeof(hospt),1,fp)==1){
    if(Pid == hospt.patientId){
      printf("\nEnter Patient ID: ");
      scanf("%d",&hospi.patientId);
      printf("\nEnter Patient First Name: ");
      scanf("%s",hospi.fname);
      fflush(stdin);
      printf("\nEnter Patient Last Name: ");
      scanf("%s",hospi.lname);
      printf("\nEnter Patient sex(M for male F for Female): ");
      scanf("%s",hospi.gender);
      printf("\nEnter Patient Age: ");
      scanf("%d",&hospi.age);
      printf("\nEnter the Doctor Name which the patients is refered to: ");
      scanf("%s",hospi.ReferredTo);
      fwrite(&hospi,sizeof(hospi),1,temp);
    }else{
      fwrite(&hospi,sizeof(hospi),1,temp);
    }
  }
  fclose(fp);
  fclose(temp);
  remove("C:\\project\\record.txt");
  rename("C:\\project\\temp.txt","C:\\project\\record.txt");
}

void Search(){
  FILE *fp;
  int found_name = 0;
  char search_name[20];
  printf("\nEnter the Patient name you want to search for: ");
  scanf("%s",search_name);
  fp = fopen("C:\\project\\record.txt","r");
  while(fread(&hospi,sizeof(hospi),1,fp)==1){
    if(strcmp(search_name,hospi.fname)==0){
      found_name++;
      printf("\nPatient Id = %d\n",hospi.patientId);
      printf("Patient Fullname = %s %s\n",hospi.fname,hospi.lname);
      fflush(stdin);
      printf("Patient Gender: %s\n",hospi.gender);
      printf("Patient Age = %d\n",hospi.age);
      printf("Referred Doctorr = %s\n",hospi.ReferredTo);
      break;
    }
  }
  if(found_name==0){
    printf("\nThe Patient Name you searched for is not register in our system...:(");
  }
  fclose(fp);
}

void Delete(){
  FILE *fp,*temp;
  Hospital hospt;
  int delete_id,found = 0;
  fp = fopen("C:\\project\\record.txt","r");
  temp = fopen("C:\\project\\temp.txt","a");
  printf("\nEnter the patient id you want to Delete: ");
  scanf("%d",&delete_id);
  while(fread(&hospt,sizeof(hospt),1,fp)==1){
    if(delete_id != hospt.patientId){
      fwrite((&hospt),sizeof(hospt),1,temp);
    }else{
      found++;
    }
  }
  fclose(fp);
  fclose(temp);
  remove("C:\\project\\record.txt");
  rename("C:\\project\\temp.txt","C:\\project\\record.txt");

  if(found>0)
  {
   printf("Data found and delete successfully\n");
  }else{
    printf("The Patiend id you want to delete is not in the File");
 }

}

Answer 1

You're writing hospi whether you update it or not; both if part and else part. You may want to write hospi when matching input, hospt otherwise.

while (fread(&hospt, sizeof(hospt), 1, fp) == 1) {
//            ^^^^^
    if (Pid == hospt.patientId) {
    //         ^^^^^
        printf("\nEnter Patient ID: ");
        scanf("%d", &hospi.patientId);
        //           ^^^^^
        /* ... */
        fwrite(&hospi, sizeof(hospi), 1, temp);
        //      ^^^^^
    } else {
        fwrite(&hospi, sizeof(hospi), 1, temp);
        //      ^^^^^
    }
}