同样是填充1亿行数组,托管和非托管差别如此之大!!

先上C#

private void button30_Click(object sender, EventArgs e) { System.Diagnostics.Stopwatch s = new System.Diagnostics.Stopwatch(); s.Start(); List<int> ar = new List<int>(100000000); int i1=10000, j1 = 10000; for (int i = 0; i < i1; i++) { for(int j=0;j<j1;j++){ ar.Add(j); } } MessageBox.Show(s.ElapsedMilliseconds.ToString()); } 

使用泛型int,并且预先分配1个亿的行堆,且处于release编译状态,耗时392ms(双核E5200)

再看C#值类型数组

private void button30_Click(object sender, EventArgs e) { System.Diagnostics.Stopwatch s = new System.Diagnostics.Stopwatch(); s.Start(); int[] ar = new int[100000000]; int i1=10000, j1 = 10000; long x=0; for (int i = 0; i < i1; i++) { for(int j=0;j<j1;j++){ ar[x++] = j; } } MessageBox.Show(s.ElapsedMilliseconds.ToString()); } 

悲剧啊,592ms....主要就是添加了一个long x计数器.

再看C++,使用boost::array

void CCListCtrl_TestDlg::OnBnClickedButton3() { // TODO: 在此添加控件通知处理程序代码 boost::array<int,_size> a_int; DWORD start = timeGetTime(); for (int i=0;i<_recount;i++) { for (int j=0;j<_size;j++) { a_int[j] = j; } } finish = timeGetTime(); duration = (double)(finish - start) / CLOCKS_PER_SEC; CString cc; cc.Format(_T("%f"),duration); showMsg(cc); } 

同样的机器,也是release状态,耗时39ms,如果使用原生数组,速度将会更快一点.这里使用boost库,可见boost库优化的很不错,效率接近原生数组了.