fraction of my C/C++ code  , text reading part

...
...
char temp[100000];
int tempsize;
int c;
...
...
tempsize=0;
while ((c=fgetc(stdin))!=EOF) {
 temp[tempsize++]=c;
}
tempsize-=2; // cut the empty line at the end of input
...
...

I got WA
but if I change it to

...
...
char temp[100000];
int tempsize;
int c;
...
...
tempsize=0;
// CHANGEs HERE !!!
while (feof(stdin)) {
 temp[tempsize++]=fgetc(stdin);
}
tempsize-=2; // cut the empty line at the end of input
...
...

I got AC.

I don't know why , but I think it might be useful for others.