1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | bool fun(unsigned n) { assert(n >0); //乘方不为正 if (!(n & (n-1))) //n的二进制只有一个1，即n==2^m; { int offset = 0;//"1"位的偏移量 while (n != 1) { n>>=1; offset++; } if (offset && !(offset&1))//偏移量为偶数，即 n == 2^(2*m),亦即n == 4^m; { return true; } } return false; } |
Archive for April, 2009
April 25, 2009
某输水管线是利用114米地面落差有压、重力流输水工程。管径2.2米，管线长度176公里，地面高程变化很大。
当输水管线建成后，首次通水时，为了防止水流速波动产生水击破坏管线，只能以每秒0.6立方米的流速由某水库向管线内灌水。
April 23, 2009
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 | #include <iostream> using namespace std; //! declaration and implementation of class Matrix class Matrix { public: Matrix(int n = 2); Matrix(const Matrix& rf); int& operator [][](int x, int y);//! operator[][] int& operator [][](int x, int y) const;//! operator[][]const Matrix& operator *=(Matrix& rt);//! operator *= private: int *p_Matrix;//! pointer to the 2D array int m_n;//! dimension of the matrix }; |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 | ORG 8000H ; position the localtion of the beginning of the commands LJMP START ; jump to the user's commands ORG 8100H ; position the localtion of the program START: MOV R0, #08H ; times of right or left shifts MOV A, #0FEH ; set LED which is lighten JNB P3.2, LOOP_L ; watch the switch which controls the shift direction LOOP_R: RR A ; branch 1: right shift MOV P1, A LCALL DELAY ; delay so that we can notice the flickering DJNZ R0, LOOP_R SJMP START LOOP_L: RL A ; branch 1: right shift MOV P1, A LCALL DELAY DJNZ R0, LOOP_L SJMP START DELAY: PUSH 06H ; subProgram impliments delaying PUSH 07H MOV R7, #0FFH LABEL1: MOV R6, #0FFH LABEL2: DJNZ R6, $ DJNZ R7, LABEL1 POP 07H POP 06H RET END |
April 22, 2009
Code:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 | #include <iostream> #include <cmath> using namespace std; double Sqrt(double x); int main() { double x; cin>>x; cout<<Sqrt(x)<<endl; return 0; } double Sqrt(double x) { const double eps = 1E-6; double x0 = x / 2, x1 = (x0 + x / x0) / 2; while(fabs(x1 - x0) > eps) { x0 = x1; x1 = (x0 + x / x0) / 2; } return x0; } |
April 19, 2009
与Windows将硬盘看做“C盘”、“D盘”几个独立的分区不同，Linux将整个文件系统看做一棵树，这棵树的树根叫做根文件系统，用/表示。各个分区通过“挂载”（mount）以文件夹的形式访问。在/中的文件夹很多，本文介绍常见文件夹的意义。Linux的目录结构确实比较复杂，但设置合理、层次鲜明。本文以FHS 2.3[1]为例进行介绍。
- .gz
- .tar.gz
- .bz2
解压1：gunzip FileName.gz
解压2：gzip -d FileName.gz
压缩：gzip FileName
解压：tar zxvf FileName.tar.gz
压缩：tar zcvf FileName.tar.gz DirName
解压1：bzip2 -d FileName.bz2
解压2：bunzip2 FileName.bz2
压缩： bzip2 -z FileName
1 2 3 4 5 6 7 8 9 10 | dpkg -i package.deb 安装包 dpkg -r package 删除包 dpkg -P package 删除包（包括配置文件） dpkg -L package 列出与该包关联的文件 dpkg -l package 显示该包的版本 dpkg –unpack package.deb 解开 deb 包的内容 dpkg -S keyword 搜索所属的包内容 dpkg -l 列出当前已安装的包 dpkg -c package.deb 列出 deb 包的内容 dpkg –configure package 配置包 |
For the safe of convenience, we firstly install the compile environment of stardict version 2.4.
# apt-get build-dep stardict |
Then, we should clear up the previous stardict, if you installed it. (the dicts will be saved).
# apt-get remove --purge stardict stardict-common |
Other packages that are not necessary, maybe.
# apt-get install libenchant-dev libgucharmap-dev gucharmap libespeak-dev |
1 2 3 4 5 6 | /*
*Filename: tri_Diagonal
*Description a solution to the tri-diagonal linear formulation
*author: HouFenglin@物理0605/DUT
*Time: 13/04/2009
*/ |