#include <stdio.h> ///for input output functions like printf, scanf
#include <stdlib.h>
#include <conio.h>
#include <windows.h> ///for windows related functions (not important)
#include <string.h> ///string operations
/** List of Global Variable */
COORD coord = {0,0}; /// top-left corner of window
/**
function : gotoxy
@param input: x and y coordinates
@param output: moves the cursor in specified position of console
*/
void gotoxy(int x,int y)
{
coord.X = x;
coord.Y = y;
SetConsoleCursorPosition(GetStdHandle(STD_OUTPUT_HANDLE),coord);
}
/** 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;
}