#include <iostream>
#include <cstdio>
#include <ctime>
using namespace std;
void funcPrint();
void funcIO();
double d =1.;

void testDump(void (*func)(void))
{
	int i=0;
	for(i=0;i<1000000;i++)
	{
		d *= 0.999;
		func();
	}
}

int main( int argc, const char *argv[] ) {
	void (*func)();
	if(*argv[1]=='1')
	{
		func = funcIO;
	}
	else
	{
		func = funcPrint;
	}
	testDump(func);
	return 0;
}

--- testSt.cc	2013-01-05 12:33:21.000000000 +0900
+++ testPt.cc	2013-01-05 12:33:09.000000000 +0900
@@ -1,11 +1,10 @@
-
-#include<iostream>
+#include<cstdio>
 using namespace std;
 
 extern double d;
 
-void funcIO()
+void funcPrint()
 {
-	cout << d;
+	printf("%g", d);
 }

real	0m3.027s
user	0m3.016s
sys	0m0.004s

dをもう一つ追加
real	0m5.991s
user	0m5.952s
sys	0m0.004s

real	0m2.230s
user	0m2.208s
sys	0m0.004s

dをもう一つ追加
real	0m4.293s
user	0m4.252s
sys	0m0.004s

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