Question

char s;
list<char> inp;

while(s=fgetc(stdin),s!=EOF)
{
    inp.push_back(s);
    printf("%c",s);
}
for(list<char>::iterator n=inp.begin();n!=inp.end();n++)
{
    cout<<*n;
}

The while loop in the above code is never being terminated ? This may happen if EOF is never recieved from stdin. How can this happen?

Answer 1

Make s an int. The fgetc() function returns an int, since EOF is defined as one.

int s;

Change it to:

while((s=fgetc(stdin)) != EOF)
{
    inp.push_back(s);
    printf("%c",s);
}

Also, EOF is not read automatically when using stdin unless you are using a pipe.

Think about it this way…

The program waits for the user to type in characters. How would the program know if EOF has been reached or the user is thinking about what to type next. The user has to send EOF to the program by typing ctrl+D.

The exception is when you have redirected stdin to a pipe. For example, if you compiled your program to a.out:

cat "myfile" | a.out