Example 15-2 gives the recursive algorithm to determine the Fibonacci number of a sequence. Figure 15-5 shows the execution of the expression rFibNum(2, 3, 5). It is evident from this figure that to...

Example 15-2 gives the recursive algorithm to determine the Fibonacci number of a sequence. Figure 15-5 shows the execution of the expression rFibNum(2, 3, 5). It is evident from this figure that to determine the fifth Fibonacci number of the sequence, the expression rFibNum(2, 3, 2) was evaluated more than once. Thus, in general, to determine a Fibonacci number some of the numbers in the Fibonacci sequence will be calculated more than once, which will result in wasting computer time and slow execution of the function. One way to prevent the recalculation of a Fibonacci number is to store it into an array. Modify the function rFibNum so that it uses an array, passed as a parameter, to store the Fibonacci numbers and prevents the recalculation of a Fibonacci number. Your modified definition must be recursive.