Write a program to show data writing and reading operation to/from a data file.

#include<stdio.h>

#include<conio.h>

struct

 {

  int roll;

  char name[25];

  float mark;

  }std;

void main()

{

  int n,i;

  FILE *fp;

  fp=fopen("d:\\cprg\student.txt","wb");

  clrscr();

  printf("\n Enter how many records: ");

  scanf("%d",&n);

  printf("enter student number name and marks for %d students",n);

  for(i=0;i<n;i++)

  {

scanf("%d%s%f",&std.roll,std.name,&std.mark);

  fwrite(&std,sizeof(std),1,fp);

  }

  fclose(fp);

  fp=fopen("d:\\cprg\student.txt","r");

  printf("\nRoll\tName\tMarks Obtained\n");

  while(fread(&std,sizeof(std),1,fp))

 printf("%d\t%s\t%f\n",std.roll,std.name,std.mark);

  fclose(fp);

  getch();

  }