专业软件应用(四)-双语.ppt

solve 在得不到解析解时，会给出数值解。 If the analytic solution can not be obtained, then the numerical solution will be obtained. 例：解方程组 [x,y,z]=solve(x+2*y-z=27,x+z=3, ... x^5+3*y^2=28,x,y,z) 六、matlab程序流的控制(program control) matlab的控制语句同c语言有相似之处, 但没有c 语言复杂，灵活和多变。因而语法比较简单，容易掌握。 Program control in matlab has some similar like as in C language, while not complicated as C language, it is flexible and changeable. So its grammar is very simple and easy to master. echo 指令— 用来控制m文件在执行过程中是否显示 control the display of the results during the program running. echo on — 打开所有命令文件的显示方式 open echo off — 关闭所有命令文件的显示方式 off echo — 在以上两者间切换 switch echo对于命令文件函数文件有所不同，命令文件用法简单，函数对所有命令起作用。 echo file on — 打开file函数文件的显示方式 echo file off — 关闭file函数文件的显示方式 echo file — 切换file函数文件的显示方式 echo on all — 打开所有函数文件的显示方式 echo off all —关闭所有函数文件的显示方式 input —— 提示用户从键盘输入数值、字符串、表达式。 remand the user to input the number, string or express by the keyboard. 例：n=input(How many apples= ) How many apples= 5 n = 5 pause —— 暂停，等待用户响应 Pause and waiting for response. 可令m文件执行暂停，并在继续执行前按任意个键 。 Type anykey to continually running the m file. keyboard —— 与input类似，功能更强 similar as input, but more powerful. keyboard 调用键盘与调用m文件一样，当keyboard在m文件中出现时，它停止文件的执行并控制键盘，用于修改程序。用dbquit指令退出。 Call the keyboard is just like call the m file, when the keyboard is shown in m file, pause the program and control the keyboard to revise the program. Using the dbquit to return. break —— 中断 break 中断for, while循环语句的执行，在嵌套循环结构中， break进从最里层循环推出。 Break can stop the for and while loop, and return from the innermost layer in the nested loop structure 七、文件操作(files operation) matlab文件输入、输出（I/O）函数允许把其它格式的数据文件直接读进matlab，它是以c语言文件I/O函数为基础的。 Matlab can input and output data files into its workspace, which is based on the C language. 打开和关闭文件（fopen,