数据结构与程序设计 C 基础知识Review

1、7/18/2022数据结构与程序设计1The Solution: Classes Objects Methods Eg: Life configuration;configuration.initialize( );configuration.update();configuration.print();7/18/2022数据结构与程序设计2Life Game ImplementSet up a Life configuration as an initial arrangement of living and dead cells.Print the Life configuration.W

2、hile the user wants to see further generations:Update the configuration by applying the rules of the Life game.Print the current configuration.7/18/2022数据结构与程序设计3良好的编程风格类、变量及函数的命名要简短有意义P12-13在程序、函数或方法前写上精确的功能描述。文档、注释要在编程的同时，甚至是在编程之前完成。Guidelines P13-14工程的模块化至顶向下，模块细分使用类来建模（STL,MFC）每个函数只做一件事情，代码尽量不要超

3、出一页精确每个函数的功能，Input（Const 说明）, Output, Inout参数函数接口要简单，尽量少用全局变量，用时要有文档注明7/18/2022数据结构与程序设计4课堂练习P17 Exercises 1.3 E1(a)P17 Exercises 1.3 E47/18/2022数据结构与程序设计5C+ 基础知识Review7/18/2022数据结构与程序设计6C+ 基础知识Review.h fileclass declaration and function headers.cpp or .c fileclass or function implementation7/18/202

4、2数据结构与程序设计7C+ 基础知识Review#includeUsed to include header files#include for library files#include “file.h” for local files and library files7/18/2022数据结构与程序设计8C+ 基础知识ReviewI/OTo use Input or Output, you need to use:#include Standard input is cin and uses cin xCoord;Standard output is cout and uses cout

5、 “(“ xCoord “,” yCoord “)” n;int* x = new intn; /动态数组char s6;char s = “CS225”; /with a null character at the end 07/18/2022数据结构与程序设计10C+ 基础知识ReviewParameter Passing3 ways to pass a variable to a function:Pass-by-value (C and C+)Pass-by-pointer (C and C+)Pass-by-reference (C+ only)7/18/2022数据结构与程序设计1

6、1Parameter Passing7/18/2022数据结构与程序设计12Value Example Result7/18/2022数据结构与程序设计13Parameter Passing7/18/2022数据结构与程序设计14Pointer Example Result7/18/2022数据结构与程序设计15Parameter Passing7/18/2022数据结构与程序设计16Reference Example Result7/18/2022数据结构与程序设计17Life Coding: The Life Class Declaration P22const int maxrow =

7、20, maxcol = 60; / grid dimensionsclass Life public: void initialize(); void print(); void update();private: int gridmaxrow + 2maxcol + 2; / allows for two extra rows and columns int neighbor_count(int row, int col);7/18/2022数据结构与程序设计18Life Coding: The Main Program P8void main() / Program to play Co

8、nways game of Life. Life configuration; instructions(); configuration.initialize(); configuration.print(); cout Continue viewing new generations? endl; while (user_says_yes() configuration.update(); configuration.print(); cout Continue viewing new generations? endl; 7/18/2022数据结构与程序设计19分析: Life Meth

9、odsint Life : neighbor count(int row, int col)Pre: The Life object contains a configuration, and the coordinatesrow and col define a cell inside its hedge.Post: The number of living neighbors of the specied cell isreturned.void Life : update( )Pre: The Life object contains a configuration.Post: The

10、Life object contains the next generation of configuration.7/18/2022数据结构与程序设计20分析: Life Methodsvoid instructions( )Pre: None.Post: Instructions for using the Life program are printed.void Life : initialize( )Pre: None.Post: The Life object contains a configuration specified by the user.void Life : pr

11、int( )Pre: The Life object contains a configuration.Post: The configuration is written for the user.7/18/2022数据结构与程序设计21Life Coding: The Life:initialize Method P23void Life:initialize() int row, col; for (row = 0; row = maxrow+1; row+) for (col = 0; col = maxcol+1; col+) gridrowcol = 0; cout List th

12、e coordinates for living cells. endl; cout Terminate the list with the special pair -1 -1 row col; while (row != -1 | col != -1) if (row = 1 & row = 1 & col = maxcol) gridrowcol = 1; else cout Column col is out of range. endl; else cout Row row is out of range. row col; 7/18/2022数据结构与程序设计22Life Codi

13、ng: The Life:neighbor_count Method P23int Life:neighbor_count(int row, int col) int i, j; int count = 0; for (i = row - 1; i = row + 1; i+) for (j = col - 1; j = col + 1; j+) count += gridij; / Increase the count if neighbor is alive. count -= gridrowcol; / Reduce count, since cell is not its own ne

14、ighbor. return count;7/18/2022数据结构与程序设计23Life Coding: The Life:update Method P24void Life:update() int row, col; int new_gridmaxrow + 2maxcol + 2; /Prevent next generation from affecting this generation for (row = 1; row = maxrow; row+) for (col = 1; col = maxcol; col+) switch (neighbor_count(row, c

15、ol) case 2: new_gridrowcol = gridrowcol; / Status stays the same. break; case 3: new_gridrowcol = 1; / Cell is now alive. break; default: new_gridrowcol = 0; / Cell is now dead. for (row = 1; row = maxrow; row+) for (col = 1; col = maxcol; col+) gridrowcol = new_gridrowcol;7/18/2022数据结构与程序设计24Life C

16、oding: The Life:print Method P26void Life:print() int row, col; cout nThe current Life configuration is: endl; for (row = 1; row = maxrow; row+) for (col = 1; col = maxcol; col+) if (gridrowcol = 1) cout *; else cout ; cout endl; cout endl;7/18/2022数据结构与程序设计25Life Coding: The utility function instru

17、ctions P25void instructions() cout Welcome to Conways game of Life. endl; cout This game uses a grid of size maxrow by maxcol in which endl; cout each cell can either be occupied by an organism or not. endl; cout The occupied cells change from generation to generation endl; cout according to the num

18、ber of neighboring cells which are alive. endl;7/18/2022数据结构与程序设计26Life Coding: The utility function user_says_yes P27bool user_says_yes() int c; bool initial_response = true; do / Loop until an appropriate input is received. if (initial_response) cout “ (y,n)? ” flush; /清除缓冲区 else cout Respond with

19、 either y or n: c; /会自动过滤n， t， 等效于char c;do / Ignore white space. c = cin.get(); while (c = n | c = | c = t);7/18/2022数据结构与程序设计28Life Coding: The utility function user_says_yes P27bool user_says_yes() /改进代码 char c; cout “ (y,n)? ” c; while (c != y & c != Y & c != n & c != N) / Loop until an appropri

20、ate input is received. cout Respond with either y or n: c; return (c = y | c = Y);7/18/2022数据结构与程序设计29VC Life_Game 实现目录Life_Game下例程参考P23 图7/18/2022数据结构与程序设计30上机作业用VC实现上述Life_Game 7/18/2022数据结构与程序设计31程序调试的一些方法可能的程序分支都思考一遍在主程序的关键点添加重要变量输出语句或设置断点在函数的调用前后添加重要变量输出语句或设置断点7/18/2022数据结构与程序设计32软件测试测试只能证明BUG的

21、存在，永远不能证明程序的正确性。测试的主要方法黑盒法 P30(a) Easy values(b) Typical, realistic values(c) Extreme values(d) Illegal values白盒法 P31:Trace all the paths through theprogram.7/18/2022数据结构与程序设计33本章小结（points and pitfalls）1. To improve your program, review the logic. Dont optimizecode based on a poor algorithm.2. Never

22、 optimize a program until it is correct and working.3. Dont optimize code unless it is absolutely necessary.4. Keep your functions short; rarely should any function be morethan a page long.5. Be sure your algorithm is correct before starting to code.6. Verify the intricate（复杂的） parts of your algorit

23、hm.7. Keep your logic simple.8. Be sure you understand your problem before you decide howto solve it.9. Be sure you understand the algorithmic method before youstart to program.10. In case of difficulty, divide a problem into pieces and think ofeach part separately.7/18/2022数据结构与程序设计34本章小结（points an

24、d pitfalls）11. The nouns that arise in describing a problem suggest usefulclasses for its solution; the verbs suggest useful functions.12. Include careful documentation (as presented in Section 1.3.2)with each function as you write it.13. Be careful to write down precise preconditions and postconditionsfor every function.14. Include error checking at the beginning of