Net面向对象程序设计-11-理解参数数组-2010-2011-2

1孙月江[e-mail]1第11章理解参数数组本章内容使用Params关键字接受任意数量的参数使用Params关键字和object类型，接受任意类型、任意数量的参数比较获取参数数组的方法和获取可选参数的方法重载是指在相同的作用域内，声明两个或多个同名的方法如果需要对不同类型的参数执行相同的操作，重载非常有用示例：classConsole{publicstaticvoidWriteLine(intparameter)...publicstaticvoidWriteLine(doubleparameter)...publicstaticvoidWriteLine(decimalparameter)...}假如发生变化的不是参数类型，而是参数的数量，重载就有些力不从心了例如：Sum方法publicstaticintSum(inta,intb){intsumTotal;sumTotal=a+b;returnsumTotal;}多参数publicstaticintSumThree(inta,intb,intc)publicstaticintSumFour(inta,intb,intc,intd)publicstaticintSumTen(inta,intb,intc,intd,inte,intf,intg,inth,inti,intj)数组在方法中的使用数组元素作为方法中的参数privatestaticdecimalMaxAmount(decimala,decimalb)decimal[]person1Sales={40000,10000,25000,50000,33000,60000};decimal[]person2Sales={80000,3000,110000,40000,33000,59000};...MaxArray(person1Sales[0],person2Sales[0]...01:usingSystem;02:03:classMaxSales04:{05:publicstaticvoidMain()06:{07:decimal[]person1Sales={40000,10000,25000,50000,33000,60000};08:decimal[]person2Sales={80000,3000,110000,40000,33000,59000};09:10:Console.WriteLine(Maxindividualsalesforeachofthefirstsixmonths:);11:for(inti=0;i6;i++)12:{13:Console.WriteLine(Month{0}:{1,11:C},14:i+1,MaxAmount(person1Sales[i],person2Sales[i]));15:}16:}17:18:privatestaticdecimalMaxAmount(decimala,decimalb)19:{20:if(ab)21:returna;22:else23:returnb;24:}25:}Maxindividualsalesforeachofthefirstsixmonths:Month1:$80,000.00Month2:$10,000.00Month3:$110,000.00Month4:$50,000.00Month5:$33,000.00Month6:$60,000.00数组引用作为方法参数要指定一个方法接受数组对象引用类型的参数，需要在方法头中包含适当的形式参数。publicstaticintSum(uint[]numbers)提供给方法调用的数组变量参数并不包含任何方括号03:classAverageAgeCalculator04:{05:publicstaticvoidMain()06:{07:byte[]agesScoutCamp=newbyte[4];08:byte[]agesSpaceShuttle=newbyte[6];10:Console.WriteLine(Enteragesfor{0}scouts:,agesScoutCamp.Length);11:for(inti=0;iagesScoutCamp.Length;i++)12:{13:Console.Write(Enterageforscoutnumber{0}:,i+1);14:agesScoutCamp[i]=Convert.ToByte(Console.ReadLine());15:}16:Console.WriteLine(Averageageofscouts:+AverageAge(agesScoutCamp));17:18:Console.WriteLine(\nEnteragesfor{0}astronauts,agesSpaceShuttle.Length);19:for(inti=0;iagesSpaceShuttle.Length;i++)20:{21:Console.Write(Enterageforastronautnumber{0}:,i+1);22:agesSpaceShuttle[i]=Convert.ToByte(Console.ReadLine());23:}24:Console.WriteLine(Averageageofastronauts:+AverageAge(agesSpaceShuttle));25:}27:publicstaticbyteAverageAge(byte[]ages)28:{29:intageSum=0;30://ThesumofallagesisassignedtoageSum31:for(inti=0;iages.Length;i++)32:ageSum+=ages[i];33://Calculatetheaverageageandreturnitbacktothecaller34:return(byte)(ageSum/ages.Length);35:}36:}Enteragesfor4scouts:Enterageforscoutnumber1:10enterEnterageforscoutnumber2:9enterEnterageforscoutnumber3:8enterEnterageforscoutnumber4:9enterAverageageofscouts:9Enteragesfor6astronautsEnterageforastronautnumber1:34enterEnterageforastronautnumber2:38enterEnterageforastronautnumber3:30enterEnterageforastronautnumber4:35enterEnterageforastronautnumber5:33enterEnterageforastronautnumber6:34enterAverageageofastronauts:34使用数组作为方法的返回值01:usingSystem;02:03:classReturnMaxSalesArray04:{05:publicstaticvoidMain()06:{07:decimal[]person1Sales={40000,10000,25000,50000,33000,60000};08:decimal[]person2Sales={80000,3000,110000,40000,33000,59000};09:decimal[]maxSales;10:11:maxSales=MaxArray(person1Sales,person2Sales);12:Console.WriteLine(Maxindividualsalesforeachofthefirstsixmonths:);13:for(inti=0;i6;i++)14:{15:Console.WriteLine(Maxsalesmonth{0}:{1,12:C},(i+1),maxSales[i]);16:}17:}19:privatestaticdecimal[]MaxArray(decimal[]sales1,decimal[]sales2)20:{21:decimal[]maxSales=newdecimal[sales1.Length];22:23:for(inti=0;imaxSales.Length;i++)24:{25:maxSales[i]=MaxAmount(sales1[i],sales2[i]);26:}27:returnmaxSales;28:}29:30:privatestaticdecimalMaxAmount(decimala,decimalb)31:{32:if(ab)33:returna;34:else35:returnb;36:}37:}11.1使用数组参数示例：写一个方法判断作为参数传递的一组值中的最小值classUtil{publicstaticintMin(int[]paramList){if(paramList==null||paramList.Length==0){thrownewArgumentException(Util.Min:notenougharguments);}intcurrentMin=paramList[0];foreach(intiinparamList){if(icurrentMin){currentMin=i;}}returncurrentMin;}}为了使用Min方法来判断2个int值的最小值，需要如下修改int[]array=newint[2];array[0]=first;array[1]=second;intmin=Util.Min(array);为了使用Min方法来判断2个int值的最小值，需要如下修改int[]array=newint[3];array[0]=first;array[1]=second;array[2]=third;intmin=Util.Min(array);缺点：必须编写额外的代码填充传入的数组11.1.1声明params数组classUtil{publicstaticintMin(paramsint[]paramList){//codeexactlyasbefore}}Params关键字对Min的作用是：调用该方法时，可以传递任意数量的整数参数intmin=Util.Min(first,second);自动转换成：int[]array=newint[2];array[0]=first;array[1]=second;intmin=Util.Min(array);01:usingSystem;03:classSumCalculator04:{05:publicstaticvoidMain()06:{07:intresult1,result2,result3,result4,result5;08:int[]myNumbers={4,10,6,8,2};10:result1=Sum(3,5);11:result2=Sum(10,20,30);12:result3=Sum(1,2,3,4,5,6,7,8,9,10);13:result4=Sum(myNumbers);14:result5=Sum();16:Console.WriteLine(\nEndresults:{0},{1},{2},{3},{4},17:result1,result2,result3,result4,result5);18:}20:publicstaticintSum(paramsint[]numbers)21