由于F#2.0已经成为VS2010的一部分,我对F#感兴趣.我想知道使用它的意义是什么.我读了一下,我做了一个基准测量函数调用.
我使用了Ackermann的功能:)
我使用了Ackermann的功能:)
C#
sealed class Program
{
public static int ackermann(int m,int n)
{
if (m == 0)
return n + 1;
if (m > 0 && n == 0)
{
return ackermann(m - 1,1);
}
if (m > 0 && n > 0)
{
return ackermann(m - 1,ackermann(m,n - 1));
}
return 0;
}
static void Main(string[] args)
{
Stopwatch stopWatch = new Stopwatch();
stopWatch.Start();
Console.WriteLine("C# ackermann(3,10) = " + Program.ackermann(3,10));
stopWatch.Stop();
Console.WriteLine("Time required for execution: " + stopWatch.ElapsedMilliseconds + "ms");
Console.ReadLine();
}
}
C
class Program{
public:
static inline int ackermann(int m,int n)
{
if(m == 0)
return n + 1;
if (m > 0 && n == 0)
{
return ackermann(m - 1,1);
}
if (m > 0 && n > 0)
{
return ackermann(m - 1,n - 1));
}
return 0;
}
};
int _tmain(int argc,_TCHAR* argv[])
{
clock_t start,end;
start = clock();
std::cout << "CPP: ackermann(3,10) = " << Program::ackermann(3,10) << std::endl;
end = clock();
std::cout << "Time required for execution: " << (end-start) << " ms." << "\n\n";
int i;
std::cin >> i;
return 0;
}
F#
// Ackermann let rec ackermann m n = if m = 0 then n + 1 elif m > 0 && n = 0 then ackermann (m - 1) 1 elif m > 0 && n > 0 then ackermann (m - 1) (ackermann m (n - 1)) else 0 open System.Diagnostics; let stopWatch = Stopwatch.StartNew() let x = ackermann 3 10 stopWatch.Stop(); printfn "F# ackermann(3,10) = %d" x printfn "Time required for execution: %f" stopWatch.Elapsed.TotalMilliseconds
Java的
public class Main
{
public static int ackermann(int m,int n)
{
if (m==0)
return n + 1;
if (m>0 && n==0)
{
return ackermann(m - 1,1);
}
if (m>0 && n>0)
{
return ackermann(m - 1,n - 1));
}
return 0;
}
public static void main(String[] args)
{
System.out.println(Main.ackermann(3,10));
}
}
那时
C#= 510ms
c = 130ms
F#= 185ms
Java = Stackoverflow
