The main features of this project include basic file handling operations; you will learn how to add, list, modify and delete data to/from file. The source code is relatively short, so thoroughly go through the mini project, and try to analyze how things such as functions, pointers, files, and arrays are implemented.
Currently, listed below are the only features that make up this project, but you can add new features as you like to make this project a better one!
- Add record
- List record
- Modify record
- Delete record
The functions used in this project are simple and they basically manipulate file handling and data structures. So, I will only describe the gotoxy function used in this project. Try to understand how this functions works as you may want to use it or find it used in many other C mini projects.
CODE:
#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;
}
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