employment management system

/// List of library functions
#include <stdio.h> ///for input output functions like printf, scanf
#include <stdlib.h>
#include <conio.h>
#include <string.h>  ///string operations
/** Main function started */
int main(){
    FILE *fp, *ft; /// file pointers
    char another, choice;

    /** structure that represent a employee */
    struct emp{
char name[40]; ///name of employee
int age; /// age of employee
float bs; /// basic salary of employee
    };

    struct emp e; /// structure variable creation

    char empname[40]; /// string to store name of the employee

    long int recsize; /// size of each record of employee

    /** open the file in binary read and write mode
    * if the file EMP.DAT already exists then it open that file in read write mode
    * if the file doesn't exit it simply create a new copy
    */
    fp = fopen("EMP.DAT","rb+");
    if(fp == NULL){
fp = fopen("EMP.DAT","wb+");
if(fp == NULL){
   printf("Connot open file");
   exit(1);
}
    }

    /// sizeo of each record i.e. size of structure variable e
    recsize = sizeof(e);

    /// infinite loop continues untile the break statement encounter
    while(1){
system("cls"); ///clear the console window
gotoxy(30,10); /// move the cursor to postion 30, 10 from top-left corner
printf("1. Add Record"); /// option for add record
gotoxy(30,12);
printf("2. List Records"); /// option for showing existing record
gotoxy(30,14);
printf("3. Modify Records"); /// option for editing record
gotoxy(30,16);
printf("4. Delete Records"); /// option for deleting record
gotoxy(30,18);
printf("5. Exit"); /// exit from the program
gotoxy(30,20);
printf("Your Choice: "); /// enter the choice 1, 2, 3, 4, 5
fflush(stdin); /// flush the input buffer
choice  = getche(); /// get the input from keyboard
switch(choice){
   case '1':  /// if user press 1
system("cls");
fseek(fp,0,SEEK_END); /// search the file and move cursor to end of the file
/// here 0 indicates moving 0 distance from the end of the file

another = 'y';
while(another == 'y'){ /// if user want to add another record
   printf("\nEnter name: ");
   scanf("%s",e.name);
   printf("\nEnter age: ");
   scanf("%d", &e.age);
   printf("\nEnter basic salary: ");
   scanf("%f", &e.bs);

   fwrite(&e,recsize,1,fp); /// write the record in the file

   printf("\nAdd another record(y/n) ");
   fflush(stdin);
   another = getche();
}
break;
   case '2':
system("cls");
rewind(fp); ///this moves file cursor to start of the file
while(fread(&e,recsize,1,fp)==1){ /// read the file and fetch the record one record per fetch
   printf("\n%s %d %.2f",e.name,e.age,e.bs); /// print the name, age and basic salary
}
getch();
break;

   case '3':  /// if user press 3 then do editing existing record
system("cls");
another = 'y';
while(another == 'y'){
   printf("Enter the employee name to modify: ");
   scanf("%s", empname);
   rewind(fp);
   while(fread(&e,recsize,1,fp)==1){ /// fetch all record from file
if(strcmp(e.name,empname) == 0){ ///if entered name matches with that in file
   printf("\nEnter new name,age and bs: ");
   scanf("%s%d%f",e.name,&e.age,&e.bs);
   fseek(fp,-recsize,SEEK_CUR); /// move the cursor 1 step back from current position
   fwrite(&e,recsize,1,fp); /// override the record
   break;
}
   }
   printf("\nModify another record(y/n)");
   fflush(stdin);
   another = getche();
}
break;
   case '4':
system("cls");
another = 'y';
while(another == 'y'){
   printf("\nEnter name of employee to delete: ");
   scanf("%s",empname);
   ft = fopen("Temp.dat","wb");  /// create a intermediate file for temporary storage
   rewind(fp); /// move record to starting of file
   while(fread(&e,recsize,1,fp) == 1){ /// read all records from file
if(strcmp(e.name,empname) != 0){ /// if the entered record match
   fwrite(&e,recsize,1,ft); /// move all records except the one that is to be deleted to temp file
}
   }
   fclose(fp);
   fclose(ft);
   remove("EMP.DAT"); /// remove the orginal file
   rename("Temp.dat","EMP.DAT"); /// rename the temp file to original file name
   fp = fopen("EMP.DAT", "rb+");
   printf("Delete another record(y/n)");
   fflush(stdin);
   another = getche();
}
break;
   case '5':
fclose(fp);  /// close the file
exit(0); /// exit from the program
}
    }
    return 0;
}