Created
February 18, 2016 02:27
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Using the substitution model to visualize tail recursion
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| def factorial(n: Int) : Int = { | |
| def factorialTR(acc: Int, n: Int) : Int = if (n == 1) acc else factorialTR(acc * n, n - 1) | |
| factorialTR(1, n) | |
| } | |
| factorial(4) = | |
| factorialTR(1, 4) = | |
| if (4 == 1) 1 else factorialTR(1 * 4, 4 - 1) = | |
| factorialTR(1 * 4, 4 - 1) = | |
| factorialTR(4, 3) = | |
| if (3 == 1) 4 else factorialTR(4 * 3, 3 - 1) = | |
| factorialTR(4 * 3, 3 - 1) = | |
| factorialTR(12, 2) = | |
| if (2 == 1) 12 else factorialTR(12 * 2, 2 - 1) = | |
| factorialTR(12 * 2, 2 - 1) = | |
| factorialTR(24, 1) = | |
| if (1 == 1) 24 else factorialTR(24 * 1, 1 - 1) = | |
| 24 |
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