聊城大学：《MATLAB语言及应用 MATLAB Language and Application》课程教学资源（课件讲稿，上）第2章 程序设计和M文件（2.3-2.5）

For example,suppose we have a large program containing a construct like the one that follows. if (test1) if (test2) ■ if (test3) ■ … end ■ end end 11

11 „ For example, suppose we have a large program containing a construct like the one that follows. „ … „ if (test1) „ … „ if (test2) „ … „ if (test3) „ ... „ end „ … „ end „ … „ end

例：根据考试成绩，分成AB/CD/F等级。 grade≥95 A 95>grade≥ 86 B 86>grade≥76 C 76>grade≥66 D 66>grade≥0 F ■用f结构进行分级描述： (a)多个if语句结构 (b)嵌套f结构 12

12 例：根据考试成绩，分成A/B/C/D/F等级。 „ grade ≥ 95 A „ 95 > grade ≥ 86 B „ 86 > grade ≥ 76 C „ 76 > grade ≥ 66 D „ 66 > grade ≥ 0 F „ 用 if 结构进行分级描述： „ (a) 多个if语句结构 „ (b) 嵌套 if 结构

Solution (a)多个if语句结构 if grade >=95.0 disp('The grade is A.'); elseif grade >=86.0 disp("The grade is B.'); elseif grade >=76.0 ■ disp("The grade is C.'); elseif grade >=66.0 ■ disp("The grade is D.'); ■ else ■ disp("The grade is F.'); end 13

13 Solution „ (a) 多个if语句结构 „ if grade > =95.0 „ disp('The grade is A.'); „ elseif grade > =86.0 „ disp('The grade is B.'); „ elseif grade > =76.0 „ disp('The grade is C.'); „ elseif grade > =66.0 „ disp('The grade is D.'); „ else „ disp('The grade is F.'); „ end

■ (b)嵌套f结构 if grade >=95.0 disp('The grade is A.'); else if grade >=86.0 disp("The grade is B.); else ■ if grade >=76.0 ■ disp('The grade is C.); ■ else ■ if grade >=66.0 ■ disp('The grade is D.) ◆ else ■ disp('The grade is F.); end ■ end 图 end 14 ■ end

14 „ (b) 嵌套if 结构 „ if grade > =95.0 „ disp('The grade is A.'); „ else „ if grade > =86.0 „ disp('The grade is B.'); „ else „ if grade >= 76.0 „ disp('The grade is C.'); „ else „ if grade >= 66.0 „ disp('The grade is D.'); „ else „ disp('The grade is F.'); „ end „ end „ end „ end

迎 2.3.3 switch结构 switch (switch_expr) otherwise case case expr I statement1 statement1 statement2 > block3 statement2 block1 end case case expr 2 说明： statement1 ()switch_expr是标量或字 statement2 block2 符串； (2)case后面的值可以是标 量、字符串或元胞数组； 15

15 2.3.3 switch 结构 说明: (1)switch_expr是标量或字 符串； (2) case后面的值可以是标 量、字符串或元胞数组; case case_expr_1 statement1 statement2 block1 ………… case case_expr_2 statement1 statement2 block2 ………… otherwise statement1 statement2 block3 …………. end switch (switch_expr)