File operation in ‘C’ - III

Example of Write, Read, modify and delete.

---

//Write, Read, modify and delete

#include <stdio.h>

#include <conio.h>

#include <string.h>

struct emp

      {

           char name[30];

           int days,wages,sal;

      }emp;

  void add()

      {

           FILE *fptr;

           fptr=fopen("emp.txt","w");

           printf("\n\tEmployee Name:");

           fflush(stdin);

           gets(emp.name);

           fflush(stdin);

           printf("\n\tDays Worked : ");

           scanf("%d",&emp.days);

           printf("\n\tWages : ");

           scanf("%d",&emp.wages);

           emp.sal=emp.days*emp.wages;

           fwrite(&emp,sizeof(emp),1,fptr);

           fclose(fptr);

      }

  void disp()

      {

           FILE *fptr;

           fptr=fopen("emp.txt","r");

           printf("\n\n\t Employee\t\t\tDays\tWage\tSalary");

           printf("\n\t   Name");

           printf("\n\t======================================================");

           while(fread(&emp,sizeof(emp),1,fptr)==1)

              {

                   printf("\n\t %-30s\t %d\t %d\t %d",emp.name,emp.days, emp.wages, emp.sal);

              }

           printf("\n\t======================================================");

      }

  void modify()

      {

           char name[20];

           FILE *fptr,*fptr1;

           int flag=0;

           fptr=fopen("emp.txt","r");

           fptr1=fopen("temp.txt","w");

           printf("\n\tEnter Employee Name to Modify: ");

           fflush(stdin);

           gets(name);

           fflush(stdin);

           while(fread(&emp,sizeof(emp),1,fptr)==1)

              {

                   if(stricmp(emp.name,name)==0)

                        {

                            flag=1;

                            printf("\n\tEnter New Days & Wage:");

                            scanf("%d%d",&emp.days,&emp.wages);

                            emp.sal=emp.days*emp.wages;

                        }

                   fwrite(&emp,sizeof(emp),1,fptr1);

              }

           if(flag==1)

              {

                   printf("\n\tThe Profile is Modified");

              }

           else

              {

                   printf("\n\tRecord is Not Found!!");

              }

           fclose(fptr);

           fclose(fptr1);

           remove("emp.txt");

           rename("temp.txt","emp.txt");

      }

  void del()

      {

           char name[20];

           FILE *fptr,*fptr1;

           int flag=0;

           fptr=fopen("emp.txt","r");

           fptr1=fopen("temp.txt","w");

           printf("\n\tEnter Employee Name to Delete : ");

           fflush(stdin);

           gets(name);

           fflush(stdin);

           while(fread(&emp,sizeof(emp),1,fptr)==1)

              {

                   if(stricmp(emp.name,name)!=0)

                        {

                            fwrite(&emp,sizeof(emp),1,fptr1);

                        }

                   else

                        {

                            flag=1;

                        }

              }

           if(flag==1)

              {

                   printf("\n\tThe Profile is Deleted");

              }

           else

              {

                   printf("\n\tRecord is Not Found!!");

              }

           fclose(fptr);

           fclose(fptr1);

           remove("emp.txt");

           rename("temp.txt","emp.txt");

      }

  void main()

      {

           int c=0;

           clrscr();

           while(c<5)

              {

                   printf("\n\n\t1. Add");

                   printf("\n\t2. Display");

                   printf("\n\t3. Delete");

                   printf("\n\t4. Modify");

                   printf("\n\t5. Exit");

                   printf("\n\tYour Choice : ");

                   scanf("%d",&c);

                   switch(c)

                        {

                            case 1:add();break;

                            case 2:disp();break;

                            case 3:del();break;

                            case 4:modify();break;

                        }

              }

           getch();

      }