例6.1 使用运算符==和equals方法进行字符串比较.doc

例6.1 使用运算符“=”和Equals方法进行字符串比较。/程序清单P6_1.csusing System;public class Mytokenizingpublic static void Main(string args)string str1 = Visual Studio;/常量编译时分配空间,且内存中只保留一份string str2 = Visual Studio;/常量Visual Studio的引用赋值给str1和str2string st1 = Visula ;string st2 = Visula ;string s1 = Studio;string s2 = Studio;string str = st1+s1;/str1+s1执行时分配空间，并将引用赋值给str string st = st2+s2; /st2+s2执行时分配空间，并将引用赋值给strConsole.WriteLine(str1=str2);/str1与str2有相同的引用,相同的内容Console.WriteLine(str1.Equals(str2);Console.WriteLine(str=st);/str与st有相同的内容,不同的引用Console.WriteLine(str.Equals(st);例6.2 将字符串转换为字符数组。/程序清单P6_2using System;namespace P6_2public class ArrayTestpublic static void Main()string str = visual Studio;/字符串全部复制到字符数组char ch1 = str.ToCharArray();/字符串部分复制到字符数组char ch2 = str.ToCharArray(7,6);/改变数组元素的值,v在数组和字符串位置相同ch1str.IndexOf(v) = V;/字符数组转换成字符串,用于显示string st = new string(ch1);Console.WriteLine(st);/用new string(ch2)直接返回字符串Console.WriteLine(new string(ch2);char ch3 = new char20;char ch4 = new char20;/复制字符串前6个字符到字符数组str.CopyTo(0,ch3,3,6);/复制字符串后6个字符到字符数组str.CopyTo(7,ch4,3,6);/改变数组元素的值ch33 = V;/显示字符数组ch3的元素Console.WriteLine(new string(ch3);/显示字符数组ch4的元素Console.WriteLine(new string(ch4);例6.3 字符串的子串操作。/程序清单P6_3using System;namespace P6_3public class ArraySubstringTestpublic static void Main()string str = visual Studio .NET;/提取字符串中第7个位置开始的6个字符的子串string subStr1 = str.Substring(7,6);Console.WriteLine(subStr1);string str1 = null;/判断visual是否为字符串str的子串if(str.StartsWith(visual)/删除字符串中第0个位置开始的7个字符str1 = str.Remove(0,7);Console.WriteLine(str1);string str2 = Visual+str1;Console.WriteLine(str2);例6.4 完成一个字符串数组元素的排序。/程序清单P6_4using System;namespace P6_4public class StringCompareTestpublic static void Main()string str = String,int,double,float,struct;/定义一个最大值位置变量int k=0;for(int i=0;istr.Length-1;i+)/先认为数组元素,第i位置值最大k = i;for(int j=i+1;jstr.Length;j+) /CompareTo方法比较时大小写不敏感if(stri.CompareTo(strj)0) k = j;/第j位置串大于第i位置,则k=j/k不等于i说明比较的元素后面有最大的串if(k!=i)string temp;/最大串放于数组第i位置temp = stri;stri = strk;strk = temp; for(int i=0;istr.Length;i+)Console.WriteLine(stri);例6.5 完成对字符串的修剪操作。/程序清单P6_5using System;namespace P6_5public class StringTrimTestpublic static void Main()string str = -* C# * visual Studio .NET * C# *- ;string str1 = str.Trim();/移出字符串首尾的空格Console.WriteLine(str1);char ch = ,-,*;string str2 = str.Trim(ch);/移出字符串首尾包含数组元素的字符Console.WriteLine(str2);例6.6 使用字符串连接运算符“+”。/程序清单P6_6.csusing System;public class P6_6public static void Main()string st = Visual;string s1 = st;st += Studio;string s2 = st;st += .NET C#;Console.WriteLine(s1);Console.WriteLine(s2);Console.WriteLine(st);例6.7在循环语句中使用字符串连接运算符“+”。/程序清单P6_7.csusing System;public class P6_7public static void Main()string st = ;for(char i=A;i=Z;i+)st += i; /生成新字符串,丢失原字符串控制st += ,; /生成新字符串,丢失原字符串控制st += ; /生成新字符串,丢失原字符串控制Console.WriteLine(st);例6.8 定义一个 StringBuilder 类的对象实例。/程序清单P6_8.csusing System; /StringBuilder类在命名空间System.Textusing System.Text;public class P6_8public static void Main()string str = visual Studio .NET C#;/str0=V;/程序出错,string类型不允许进行修改StringBuilder sb = new StringBuilder(str); /StringBuilder类的实例对象可进行字符的修改sb0 = V; /sb23 = A; /程序出错,超出了sb.Length范围Console.WriteLine(sb); /StringBuilder类的实例对象的长度为默认值Console.WriteLine(sb.Length); /StringBuilder类的实例对象的容量Console.WriteLine(sb.Capacity); /StringBuilder类的实例对象的最大容量Console.WriteLine(sb.MaxCapacity); sb.Length = 13;Console.WriteLine(sb); /StringBuilder类的实例对象的长度为设置值Console.WriteLine(sb.Length); /StringBuilder类的实例对象的容量Console.WriteLine(sb.Capacity); /StringBuilder类的实例对象的最大容量Console.WriteLine(sb.MaxCapacity); sb.Length = 6;Console.WriteLine(sb); Console.WriteLine(sb.Length); Console.WriteLine(sb.Capacity); Console.WriteLine(sb.MaxCapacity); 例6.9 从 StringBuilder 类的实例对象中的指定位置开始删除指定数目字符。/程序清单P6_9.csusing System;using System.Text;/StringBuilder类在命名空间System.Textpublic class P6_9public static void Main()StringBuilder sb1 = new StringBuilder(Visual Studio .NET C#);/将sb1字符串的内容前14个字符删除sb1.Remove(6,12); / sb2与sb1引用都同一字符串内容StringBuilder sb2 = sb1; /StringBuilder sb2 = sb1.Remove(6,12);/可用一句替换上面两句Console.WriteLine(sb1);Console.WriteLine(sb2);例6.10从 StringBuilder 类的实例对象中的指定位置插入指定的内容。/程序清单P6_10.csusing System;/StringBuilder类在命名空间System.Textusing System.Text;public class P6_10public static void Main()StringBuilder sb = new StringBuilder();/DateTime类的属性Now得到当前日期和时间，/Insert方法自动将日期时间转成字符串插入到sb中/sb如果得到当前日期时间为2006-6-18 12:03:20sb.Insert(0,DateTime.Now); Console.WriteLine(sb);/sb删除操作得到2006-6-18sb.Remove(9,9);/sb删除操作得到2006-618sb.Remove(6,1);/sb删除操作得到2006618sb.Remove(4,1);/sb插入操作得到2006618日sb.Insert(7,日);/sb插入操作得到20066月18日sb.Insert(5,月);/sb插入操作得到2006年6月18日sb.Insert(4,年);/sb插入操作得到公元2006年8月18日sb.Insert(0,公元);Console.WriteLine(sb);例6.11 StringBuilder 类的实例对象的Append 方法使用。/程序清单P6_11.csusing System;using System.Text;public class P6_11public static void Main()StringBuilder sb = new StringBuilder();sb.Append(公元);sb.Append(DateTime.Now.Year);sb.Append(年);sb.Append(DateTime.Now.Month);sb.Append(月);sb.Append(DateTime.Now.Day);sb.Append(日);Console.WriteLine(sb);sb.Append(DateTime.Now.Hour);sb.Append(时);sb.Append(DateTime.Now.Minute);sb.Append(分);sb.Append(DateTime.Now.Second);sb.Append(秒);Console.WriteLine(sb);例6.12 用选择排序法对数组排序。/程序清单P6_12.csusing System;class SortApppublic static void Main()int i,j,k,temp;int a=new int918,124,58,1223,334,988,43,84;for(i=0;ia.Length-1;i+)k=i;for(j=i+1;jaj)k=j;if(k!=i)temp=ai;ai=ak;ak=temp;Console.WriteLine(Result:);for(i=0;ia.Length;i+)Console.Write( 0,ai);Console.WriteLine();例6.13 使用对象作为数组元素。/程序清单P6_13.csusing System;namespace ObjectArrayclass RefArraypublic static void Main()Contact ca = new Contact3;ca0 = new Contact();ca1 = new Contact();ca2 = new Contact();ca0.m_name = 李明;ca0.m_telephone =ca1.m_name = 张鹏;ca1.m_telephone =/两个数组元素指向同一对象ca2 = ca0;ca2.m_telephone =foreach (Contact c in ca)Console.WriteLine(c.m_name + : + c.m_telephone);class Contactpublic string m_name;public string m_telephone;例6.14 简单不规则二维数组的使用。/程序清单P6_15.csusing System;public class sample1public static void Main()int i=0,j=0;int a = new int3;a0 = new int31,2,3;a1 = new int44,5,6,7;a2 = new int37,8,9; /也可用下面一句代替上面四语句/int a = new int3new int1,2,3,new int4,5,6,7,new int8,9,10for(i=0;i3;i+)for(j=0;jai.Length;j+)Console.Write( a01=2,i,j,aij);Console.WriteLine();例6.15 简单二维数组的使用。/程序清单P6_15.csusing System;public class sample1public static void Main()int i=0,j=0;int, a = new int,1,2,3,4,2,3,4,3,4,5,6,2,3,4,2,3,4,5,2,3,4,3,4,5,6,2,3,4,3,4,5,6,2,3,4;/GetLeng()方法用于获得多维数组某维度上的元素个数。in