1. Lecture 28 Sections 10.1 – 10.2 Fri, Mar 28, 2008
Recursion
Lecture 28
Sections 10.1 – 10.2
Fri, Mar 28, 2008

2. Recursion A recursive function is a function that calls on itself.
A recursive function must contain a decision structure that divides the code into two cases.
The recursive (general) case.
The nonrecursive (special) case.
The code must guarantee that eventually the nonrecursive case is called.
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Recursion

3. Advantages of Recursion
The code may be much easier to write.
Some situations are naturally recursive.
Naturally recursive data structures
Linked lists.
Binary trees.
Naturally recursive problems
Solving mazes.
Recursive sequences.
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Recursion

4. Disadvantages of Recursion
Recursive functions are generally slower than nonrecursive functions.
Excessive recursion may overflow the run-time stack.
One must be very careful when writing recursive functions; they can be tricky.
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Recursion

5. Examples of Recursive Functions
Factorial
Factorial-NR.cpp
Factorial-R.cpp
GCD
GCD-NR.cpp
GCD-R.cpp
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6. Examples of Recursive Functions
Binomial Coefficients
BinomialCoefficients-NR.cpp
BinomialCoefficients-R1.cpp
BinomialCoefficients-R2.cpp
BinomialCoefficients-R3.cpp
The Towers of Hanoi
TowersOfHanoi.cpp
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Recursion