Lecture 5

# Writebacks 3 3 returns to writebacks 3 2 writebacks

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Unformatted text preview: E. • writeback(S, 3, 3) returns to writeback(S, 3, 2). • writeback(S, 3, 2) sends T to the screen. • writeback(S, 3, 2) returns to writeback(S, 3, 1). • writeback(S, 3, 1) sends A to the screen. • writeback(S, 3, 1) returns to writeback(S, 3, 0). • writeback(S, 3, 0) sends C to the screen. • writeback(S, 3, 0) returns to the main program. 5 4 POWER: X^n = 1 X^n = X*X^(n-1) IF n = 0 Base Case IF n > 0 Recursive Case This can be translated easily into C++. However, we can do better: X^n = 1 IF n = 0 X^n = X * square of X^(n / 2) IF n is odd X^n = square of X^(n / 2) IF n is even 6 int power(int X, int N) { if (N = = 0) return 1; else { int HalfPower = power(X, N/2); if (N % 2 = = 0) return HalfPower * HalfPower; // Even n else return X * HalfPower * Halfpower; // Odd n } } 7 fib(1) = 1 fib(2) = 2 fib(n) = fib(n-1) + fib(n-2) Base Case Base Case n>2 This is a recursion that uses TWO base cases, and it breaks down a problem into TWO simpler probl...
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## This document was uploaded on 03/31/2014 for the course CS 114 at NJIT.

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