Sandbox/FunctionsAsTemplate.cpp

   1 #include "FunctionsAsTemplate.h"
   2
   3 #include <iostream>
   4 #include <map>
   5 using namespace std;
   6
   7 #include "Types.h"
   8
   9 namespace FunctionsAsTemplate
  10 {
  11     template <i64(*f)(i64)>
  12     i64 memoize(i64 x)
  13     {
  14         static std::map<i64, i64> cache;
  15         auto i = cache.find(x);
  16         if (i != cache.end())
  17             return i->second;
  18         else
  19             return cache[x] = f(x);
  20     }
  21
  22     i64 fib(i64 n) {
  23         if (n < 2)
  24             return n;
  25         else
  26             return memoize<fib>(n - 1) + memoize<fib>(n - 2);
  27     }
  28 }
  29
  30 void FunctionsAsTemplate::tests()
  31 {
  32     i64 n = 80;
  33     cout << "fib(" << n << ") = " << fib(n) << endl;
  34 }