你来测测看 谁说C比Java快？

$ java -server -XX:CompileThreshold=1 Mandelbrot 2>/dev/null
Java Elapsed 2.994
Java Elapsed 1.926
Java Elapsed 1.955
$ gcc -O8 mandelbrot.c
$ ./a.out 2>/dev/null
C Elapsed 2.03
C Elapsed 2.04
C Elapsed 2.05

import java.util.*; 

class Mandelbrot
{  
static int BAILOUT = 16;
static int MAX_ITERATIONS = 1000;            

     private static int iterate(float x, float y)
{
float cr = y-0.5f;
float ci = x;
float zi = 0.0f;
float zr = 0.0f;
int i = 0;
while (true) {
i++;
float temp = zr * zi;
float zr2 = zr * zr;
float zi2 = zi * zi;
zr = zr2 - zi2 + cr;
zi = temp + temp + ci;
if (zi2 + zr2 > BAILOUT)
return i;
if (i > MAX_ITERATIONS)
return 0;
}
} 

     public static void run2()
{
int x,y;
for (y = -39; y < 39; y++) {
System.err.print("\n");
for (x = -39; x < 39; x++) {
if (iterate(x/40.0f,y/40.0f) == 0) 
System.err.print("*");
else
System.err.print(" ");
}
}          
}

  public static void run() {
Date d1 = new Date();
for (int i = 0; i < 100; i++) run2();
Date d2 = new Date();
long diff = d2.getTime() - d1.getTime();
System.out.println("\nJava Elapsed " + diff/1000.0f);
} 

            public static void main(String args[]) {
run();
run();
run();
}
}

#include <stdio.h>
#import <sys/time.h>
#define BAILOUT 16
#define MAX_ITERATIONS 1000

int mandelbrot(float x, float y)
{
float cr = y - 0.5;
float ci = x;
float zi = 0.0;
float zr = 0.0;
int i = 0;
while(1) {
i ++;
float temp = zr * zi;
float zr2 = zr * zr;
float zi2 = zi * zi;
zr = zr2 - zi2 + cr;
zi = temp + temp + ci;
if (zi2 + zr2 > BAILOUT)
return i;
if (i > MAX_ITERATIONS)
return 0;
}     
}

void run2() {
int x,y;
for (y = -39; y < 39; y++) {
fputs("\n", stderr);
for (x = -39; x < 39; x++) {
int i = mandelbrot(x/40.0, y/40.0);
if (i==0)
fputs("*", stderr);
else
fputs(" ", stderr);
}        
}
fputs("\n", stderr);
}

void run() {
struct timeval aTv;
gettimeofday(&aTv, NULL);
long init_time = aTv.tv_sec;
long init_usec = aTv.tv_usec;
int i;
for (i = 0; i < 100; i++)
run2();
gettimeofday(&aTv,NULL);
double query_time = (aTv.tv_sec - init_time) +
(double)(aTv.tv_usec - init_usec)/1000000.0;   
printf ("C Elapsed %0.2f\n", query_time);
}

int main (int argc, const char * argv[]) {
run();
run();
run();
}

$ java -cp rhino1_6R5/js.jar -server -XX:CompileThreshold=1 
org.mozilla.javascript.tools.shell.Main -O 9 mandelbrot.js 2>/dev/null
JavaScript Elapsed 21.95
JavaScript Elapsed 17.039
JavaScript Elapsed 17.466
JavaScript Elapsed 17.147

$ gcc -O9 -march=pentium4 mandelbrot2.c
$ ./a.out 2>/dev/null
C Elapsed 1.99
C Elapsed 1.99
C Elapsed 1.99