Random Access To File: rewind() using function

How to write C program code | Random Access To File: rewind() using function

The rewind function is used to move the position of file pointer to the beginning of file. The rewind() function is useful if we want to update a given file.

struct instrument

{

int id;

char name[30];

float price;

}instr;


int main()

{

int n,i;


FILE *fp;

fp=fopen("inst1.dat","wb+");


if(fp==NULL)

{

printf("Error in opening file\n");

return 0;

}


//Accepting number of records for writing

printf("How many records do you want?\n");

scanf("%d",&n);


printf("\n--------Writing in file using fwrite-----------\n\n");

//Writing records one by one in file

for(i=0;i
{
printf("Enter the details of instrument:\n");
printf("Enter Instrument Id :\n");
scanf("%d",&instr.id);
printf("Enter Instrument Name :\n");
scanf("%s",instr.name);
printf("Enter Instrument Price :\n");
scanf("%f",&instr.price);
printf("\n");

//for writing the entire record to the file
fwrite(&instr,sizeof(instr),1,fp);
}



printf("\n\n--------Usage of rewind()-----------\n\n");

//Moving file pointer to the begining of file
fseek(fp,0,0);
printf("Position pointer in the begining-> %ld\n",ftell(fp));

//Moving file pointer to the end of file
fseek(fp,0,2);
printf("Position pointer at the end of file-> %d\n",ftell(fp));

//Moving file pointer to the begining of file using rewind
rewind(fp);
printf("Position pointer after rewind -> %d\n",ftell(fp));


fclose(fp);

}

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