When "oops" is encountered hasNextInt() returns false and the program ends.
C:\temp>java ManySquares The square of 1 is 1 The square of 6 is 36 The square of 3 is 9
This might be unfortunate since the program give no indication that there was a problem with the data.
The loop is a sentinel controlled loop. The sentinel is the end of file or something that can't be read as an integer. The following could be the contents of the input file:
1 2 3 10 11 12 13 23 45 67
The input characters form a stream, and several integers, or none, can be on a line.
A "line" is nothing more that a sequence of characters in the stream
separated by end-of-line characters.
A Scanner is perfectly happy to stop in the middle of a line if it has scanned what was expected.
It is tempting to think that the program works only with one integer per line and that each
time nextInt() runs that it eats one line.
But this is not so.
For this input, the program will write the following lines to the monitor:
The square of 1 is 1 The square of 2 is 4 The square of 3 is 9 The square of 10 is 100 The square of 11 is 121 The square of 12 is 144 The square of 13 is 169 The square of 23 is 529 The square of 45 is 2025 The square of 67 is 4489
Would it work if the input file contained the following?
10 12 13 4 6 0 -2 rats