$2.$ Reading to EOF

Input streams $($like std::cin$)$ can be used as predicates $($bools$)$ to see if they are in an error state. One such error state is having no more data to read in$.$ So an expression like this,

while $($std::cin$)\{$

$...$

$\}$

will loop until cin has nothing more to read. The expression cin $>>$ x extracts a value from the stream and puts it in x$,$ but it also returns cin. So this statement:

while $($std::cin $>>$ x$)\{$

$...$

$\}$

will keep replacing x with the next value from a stream until the stream is exhausted.

When you are testing your code by compiling and running it$,$ the above example will run until you specify that there is no more input. This is called the EOF $($End$-$Of$-$File$).$ Typing Control$-$d into the terminal sends this message.

Write a program in EOF$\_$Sum$/$main$.$cpp that reads in integers from the standard input stream until there are no more values. Print the sum of those integers.

Example input:

$254$

$19$

$2$

Expected output:

$77$