1、例5.1 找出变量 x 和 y 中的大数。/程序清单P5_1.csusing System;public class AddClasspublic static void Main()int x = 4;int y = 5;int big;/该语句完成了一个找两个数中大数的功能big = xy ? x:y;Console.WriteLine(“x 和 y 中的大数为：0“,big);例5.2 用方法完成找大数功能。/程序清单P5_2.csusing System;public class AddClasspublic static void Main()int x = 4;int y = 5;
2、int big;big = BigOne(x,y);Console.WriteLine(“x 和 y 中的大数为：0“,big);public static int BigOne(int a, int b)int m;m = ab ? a:b;return m;例 5.3求两个整数之和。/程序清单P5_3.csusing System;public class AddClasspublic static void Main()int x = 4;int y = 5;int sum;sum = SumExample.Add(x,y); /Add方法属于AddClass类,用类名调用Console
3、.WriteLine(“0 + 1 = 2“,x,y,sum);public class SumExamplepublic static int Add(int a ,int b)/形式参数a,b将会自动得到x,y的值4和5return ( a + b ); /a+b=4+5=9 通过return语句返回至调用处,所以,sum=9例 5.4 求两个整数之和。/程序清单P5_4.csusing System;public class P5_4public static void Main()/用一个语句定义三个变量也可以,但分开写更清楚int x = 4 , y = 5 , sum;/x,y作为
4、实际参数,调用Add方法sum = Add(x,y); Console.WriteLine(“0 + 1 = 2“,x,y,sum);/形式参数a,b将会自动得到x,y的值4和5public static int Add(int a ,int b)/a+b=4+5=9 通过return语句返回至调用处,所以,sum=9return ( a + b ); 例 5.5 通过实例对象调用方法。/程序清单P5_5.csusing System;public class Testpublic static void Main()/用一个语句定义三个变量也可以,分开写更清楚些int x = 4 , y =
5、 5 , sum;/实例化对象testTest test = new Test(); /通过实例对象调用方法test.Add(x,y)sum = test.Add(x,y); Console.WriteLine(“0 + 1 = 2“,x,y,sum);/实例方法Addpublic int Add(int a ,int b)return ( a + b ); 例 5.6 方法不在同一个类，通过实例对象调用方法。/程序清单P5_6.csusing System;public class P5_6public static void Main()int x = 4 , y = 5 , sum;/定
6、义对象se,并实例化SumExample se = new SumExample();/通过实例对象调用方法se.Add(x,y)sum = se.Add(x,y);Console.WriteLine(“0 + 1 = 2“,x,y,sum);public class SumExample/SumExample类的实例方法public int Add(int a ,int b) return ( a + b ); 例 5.7 用方法分别完成对数组的从小到大的排序和数组元素求和。/程序清单P5_7.csusing System;public class MainClasspublic stati
7、c void Main()int x = 4,28,23,7,9,10,5,1;Console.WriteLine(“数组排序前的元素:“);ArrayShow(x);ArraySort(x);Console.WriteLine(“数组排序后的元素:“);ArrayShow(x);int sum = ArraySum(x);Console.WriteLine(“数组元素的和为:0“,sum);public static void ArraySort(int a)for(int i=0;iaj)int temp;temp = ai;ai = aj;aj = temp;public static
8、int ArraySum(int a)int sum = 0;for(int i=0;iy?x:y;/例 5.11 测试用方法完成数据交换问题。/程序清单P5_11.cs/实际不能完成交换public class MyClass public static void Main() int a = 4;int b = 9; /将a,b变量的作为参数,只进行a和b的值传递 Swap(a,b); System.Console.WriteLine(“a = “+a+“ , b = “+b);/形参x,y接收实参a和b传来的值public static void Swap(int x,int y)/输出
9、交换前x和y值System.Console.WriteLine(“x = “+x+“ , y = “+y); int temp;temp = x; x = y; y = temp;/输出交换后x和y值System.Console.WriteLine(“x = “+x+“ , y = “+y); 例 5.12 用 ref关键字修饰方法参数，可实现两数交换功能。/程序清单P5_12.cspublic class MyClass public static void Main() int a = 4;int b = 9;/将a,b变量的引用作为参数/a和b的值也传递过去了 Swap(ref a,re
10、f b); System.Console.WriteLine(“a = “+a+“ , b = “+b); /x,y接收a,b的引用,且得到实参原来的值public static void Swap(ref int x,ref int y) System.Console.WriteLine(“x = “+x+“ , y = “+y);int temp;temp = x; x = y; y = temp;System.Console.WriteLine(“x = “+x+“ , y = “+y);例5.13 用方法对四个整型变量的值排序并打印输出。/程序清单P5_13.cspublic clas
11、s MyClass public static void Main() int a = 24;int b = 9;int c = 12;int d = 5;/变量a保存了变量a和b中的大数Compare(ref a,ref b);/变量a保存了变量a,b,c中的大数Compare(ref a,ref c);/变量a保存了变量a,b,c,d中的大数Compare(ref a,ref d);/变量b保存了变量b,c中的大数Compare(ref b,ref c);/变量b保存了变量b,c,d中的大数Compare(ref b,ref d);/变量c保存了变量c,d中的大数Compare(ref c
12、,ref d);System.Console.WriteLine(“a = 0, b = 1, c = 2, d = 3“,a,b,c,d); /x,y接收a,b的引用,且得到实参原来的值public static void Compare(ref int x,ref int y) if(x20) /为主方法设置出错判断条件sum = -1;/break语句，跳出for循环break; /根据输入的奇偶性,选奇或选偶if(i%2)!=(num%2) continue; /结束本轮循环，继续下一轮循环sum = sum * i;/终止本方法,void 返回类型方法也可以不写return语句ret
13、urn ; public static void Main ( )Console.Write(“ * 求二阶乘 *n 请输入小于20的正整数：“);int n = int.Parse(Console.ReadLine();/无需初始化int twoFact; /参数n传引用且将值带入,参数twoFact只将结果带出Fact(ref n,out twoFact);/当输入不合法时提示输入错误if(ny2)return y1;elsereturn y2;例 5.18 完成加法（Add）方法的重载之一。/程序清单P5_18.csusing System;namespace P5_18public c
14、lass AddSample/整数加方法public static int Add(int i1,int i2)return i1 + i2;/双精度数重载加方法public static double Add(double d1,double d2)return d1 + d2;/复数重载加方法public static Complex Add(Complex c1,Complex c2)Complex c;/复数的实部相加c.real = c1.real + c2.real; /复数的虚部相加c.imaginary = c1.imaginary + c2.imaginary;/返回相加的复
15、数值return c; public static void Main()int a1 = 5, a2 = 7;double b1 = 23.8, b2 = 12.3;Complex c1, c2;c1.real = 3; c1.imaginary = 5;c2.real = 7; c2.imaginary = 9;int x;double y;Complex z;/调整数重载加方法x = Add( a1, a2 );/调双精度数重载加方法y = Add( b1, b2 );/调复数重载加方法z = Add( c1, c2 );Console.WriteLine(“x=0 y=1 z=2+i3
16、“,x,y,z.real,z.imaginary);/定义一个结构,用于复数对象的定义,也可再类外定义public struct Complex /复数的实部public int real; /复数的虚部public int imaginary; 例 5.19 完成加法（Add）方法的重载之二。/程序清单P5_19.csusing System;namespace P5_19public class AddSample/Add方法为非静态方法/整数加方法public int Add(int i1,int i2)return i1 + i2;/双精度数重载加方法public double Add
17、(double d1,double d2)return d1 + d2;/复数重载加方法public Complex Add(Complex c1,Complex c2)Complex c;/复数的实部相加c.real = c1.real + c2.real; /复数的虚部相加c.imaginary = c1.imaginary + c2.imaginary; /返回相加的复数值return c; public class MainClaspublic static void Main()int a1 = 5, a2 = 7;double b1 = 23.8, b2 = 12.3;Comple
18、x c1, c2;c1.real = 3; c1.imaginary = 5;c2.real = 7; c2.imaginary = 9;int x;double y;Complex z;/定义一个对象,并实例化AddSample addSample = new AddSample();/通过实例对象调整数加方法x = addSample.Add( a1, a2 );/通过实例对象调双精度数重载加方法y = addSample.Add( b1, b2 );/通过实例对象调复数重载加方法z = addSample.Add( c1, c2 );Console.WriteLine(“x=0 y=1 z=2+i3“,x,y,z.real,z.imaginary);public struct Complex public int real; public int imaginary;
