Converting to Integers

Here is the relevant line from the program:

num = scan.nextInt();

Assignment statements work in two steps:

1. Evaluate the expression on the right of the equal sign,
2. Put the value in the variable on the left.

In this particular assignment statement, the expression on the right scans the next several characters of the input stream and converts then into an int, if they are correct. Then the numeric result is stored into num.

If the next group of characters cannot be converted, Java throws an Exception and stops your program. An Exception object contains information about what went wrong in a program. Industrial-strength programs may examine the exception and try to fix the problem. Our programs (for now) will just stop.