A Deeper Look at Receiving User Input

Any time a program receives input from the user various problems might occur. For example, in line 53 of Fig. 4.7

we assume that the user will enter an integer grade in the range 0 to 100. However, the person entering a grade could enter an integer less than 0, an integer greater than 100, an integer outside the range of values that can be stored in an int variable, a number containing a decimal point or a value containing letters or special symbols that’s not even an integer.

To ensure that the user’s input is valid, industrial-strength programs must test for all possible erroneous cases. As you progress through the book, you’ll learn various techniques for dealing with the broad range of possible input problems.