Question

Using the feof() function, on my output file i have the last value printed twice. How can i avoid that? My output should be

12
6
15
13

and i have

12
6
15
13
13

Thank you!

while(!feof(pfile1))
{       
    sum=0;
    fscanf(pfile1,"%d%d%d",&choice,&day,&val);
    if(choice==0)
    {
        i=day-1;
        a[i]=a[i]-val;
    }
    else if(choice==1)
    {
        for(i=day-1;i<=val-1;i++)
        {
            sum=sum+a[i];

        }
        fprintf(pfile2,"%d\n",sum);     
    }
}

Answer 1

One option is to check the return value of fscanf:

On success, the function returns the number of items successfully read. This count can match the expected number of readings or be less -even zero- in the case of a matching failure.
In the case of an input failure before any data could be successfully read, EOF is returned.

So, something like:

if( fscanf(pfile1,"%d%d%d",&choice,&day,&val) <= 0 )
{
    break;
}

The other option is to check for feof after executing fscanf. For example:

if( feof( pfile1 ) )
{
    return; // or something
}
do
{
    // the same loop body
}
while( ! feof( pfile1 ) );