枚举与子界类型.ppt

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1、标准数据类型实型、整型、字符型、布尔型（不必定义可以直接引用）用户定义类型P126第六章枚举类型、子界类型（先定义再引用）枚举类型格式:TYPE<枚举类型标识符>=(<标识符1>,<标识符2>,…,<标识符n>);VAR<枚举类型变量表>:<枚举类型标识符>;或VAR<枚举类型变量表>:(<标识符1>,<标识符2>,…,<标识符n>);例子:Typeday=(Sunday,Monday,Tuesday,Wednesday,Thursday,Friday,Saturday);Vartoday,tomorrow:day;或Vartoday,tomorrow:(Sunday,Monday,Tuesd

2、ay,Wednesday,Thursday,Friday,Saturday)枚举值只能是标识符（以字母开头的字母数字组合），每个枚举值只能出现在一个枚举类型定义中，并且只能在该定义中出现一次。枚举类型说明:TYPE<枚举类型标识符>=(<标识符1>,<标识符2>,…,<标识符n>);VAR<枚举类型变量表>:<枚举类型标识符>;Typet1=(‘a’,‘b’,‘c’,‘d’);t2=(1,2,3,4,5);t3=(sun,mon,tue,wed,sun);t4=(wed,thu,fri,sat);赋值Vartoday,tomorrow:(Sunday,Monday,Tuesday,Wednes

3、day,Thursday,Friday,Saturday)today:=Wednesday;tomorrow:=Thursday;运算（函数运算(ord/pred/succ)、关系运算）ord(today):=3;pred(tomorrow):=Wednesday;succ(tomorrow):=Friday;today

4、riday,Saturday);Vartoday,tomorrow:day;number:integer;Beginread(number);CASEnumberOF0:today:=Sunday;1:today:=Monday;2:today:=Tuesday;3:today:=Wednesday;4:today:=Thursday;5:today:=Friday;6:today:=SaturdayEnd;Iftoday=SaturdayThentomorrow:=SundayElsetomorrow:=succ(today);write(‘tomorrowis’);CASEtomorrow

5、OFSunday:writeln(‘Sunday’);Monday:writeln(‘Monday’);Tuesday:writeln(‘Tuesday’);Wednesday:writeln(‘Wednesday’);Thursday:writeln(‘Thursday’);Friday:writeln(‘Friday’);Saturday:writeln(‘Saturday’)EndEnd.例2:（初赛篇P153）设有四种水果：苹果、橘子、香蕉和菠萝，现要任取其中3种水果，不能重复，不计先后顺序，请编写程序列出所有可能的取法。（寒假作业）从7张扑克牌中任取三张，有几种组合方法？请编程输出所

6、有组合形式。子界类型格式:TYPE<子界类型标识符>=<常量1>..<常量2>；VAR<子界类型变量表>:<子界类型标识符>;或VAR<子界类型变量表>:<常量1>..<常量2>;例子:Typeday=(Sunday,Monday,Tuesday,Wednesday,Thursday,Friday,Saturday);schoolday=Monday..Friday;age=10..100;letter=‘a’..‘z’常量1和常量2必须是属于同一个有序类型（整型、字符型、布尔型、枚举型）的值。常量1的次序数小于常量2的次序数。VAR<子界类型变量表>:<常量1>..<常量2>;例3:输入年、

7、月，输出该月天数。（书本P133）PROGRAMmonthdays(input,output);VARyear:1..10000;month:1..12;days:28:31;BEGINread(year,month);CASEmonthOF1,3,5,7,8,10,12:days:=31;4,6,9,11:days:=30;2:IF(yearMOD4=0)AND(yearMOD100<>0)OR