C++ Primer Plus

Another Two-Argument Function

Let’s create a more ambitious function—one that performs a nontrivial calculation. Also the function illustrates the use of local variables other than the function’s formal arguments.

Many states in the United States now sponsor a lottery with some form of Lotto game. Lotto lets you pick a certain number of choices from a card. For example, you might get to pick six numbers from a card having 51 numbers. Then the Lotto managers pick six numbers at random. If your choice exactly matches theirs, you win a few million dollars or so. Our function will calculate the probability that you have a winning pick. (Yes, a function that successfully predicts the winning picks themselves would be more useful, but C++, although ...