Re: Re: Re: Fw: Infinite Joy Ride(example)

[kamesh jayachandran <kameshj@xxxxxxxxxxxxx>]

hai,

It is the simple program that is given as an example to 
illustrate random file handling in "C For Linux Programming"

The program works well if numeric values are given.If I 
give non numeric value say 'A'.It goes for infinite joy 
ride and the value of offset still remains at the value 
that I have given before giving the non numeric value.

After invalid input scanf fails to scan anymore and if I 
try to print the value of offset in if and else if prints 
the address of offset not the value.

kamesh jayachandran
//source starts here
#include<stdlib.h>
#include<stdio.h>
#define MAX 50
int main(void)
{
FILE *fp;
int data,count,array[MAX];
long offset;
for(count=0;count<MAX;count++)
array[count]=count*10;
if((fp=fopen("pp","wb"))==NULL)
{
fprintf(stderr,"Error opening File \n");
exit(1);
}
if(fwrite(array,sizeof(int),MAX,fp)!=MAX)
{
fprintf(stderr,"Error in writing data to the File\n");
exit(1);
}
fclose(fp);
if((fp=fopen("pp","rb"))==NULL)
{
fprintf(stderr,"Error in opening File\n");
exit(1);
}
while(1)
{
printf("\nEnter element to read,0-%d,-1 to quit: ",MAX-1);
scanf("%ld",&offset);
if(offset<0)
{
printf("In if %ld",offset);
break;
}
else if(offset>MAX-1)
{
printf("In else if %ld",offset);
continue;
}
if(fseek(fp,(offset*sizeof(int)),0)!=0)
{
fprintf(stderr,"Error using fseek\n");
exit(1);
}
fread(&data,sizeof(int),1,fp);
printf("\nElement %ld has value %d",offset,data);
}
fclose(fp);
return 0;
}
//source ends here