理论基础：
链表是用一组任意的存储单元来存储线性表中的数据元素。
如果结点的引用域只存储该结点直接后继结点的存储地址，则该链表叫单链表(Singly Linked List)。
单链表由头引用H唯一确定。头引用指向单链表的第一个结点，也就是把单链表第一个结点的地址放在H中。
C#实现：
1接口
引用线性表的接口IListDS<T>
2实现
首先，必须定义一个单链表的节点类。
Code1
public class Node<T>2
{3
private T data; //数据域4
private Node<T> next; //引用域5
6
7
public Node(T val)8
{9
data = val;10
next = null;11
}12
13
public Node()14
{15
data = default(T);16
next = null;17
}18
19
public T Data20
{21
get22
{23
return data;24
}25
set26
{27
data = value;28
}29
}30
public Node<T> Next31
{32
get33
{34
return next;35
}36
set37
{38
next = value;39
}40
}41
42
43
}实现主体类
Append,Insert,InsertBack三个方法实质上都是插入操作，可以考虑用overload或者override来实现，有兴趣的朋友试试。
Code1
public class LinkList<T> : IListDS<T>2
{3
private Node<T> head;4
public Node<T> Head5
{6
get7
{8
return head;9
}10
set11
{12
head = value;13
}14
}15
public LinkList()16
{17
head = null;18
}19
20
/**//// <summary>21
/// 获取长度22
/// </summary>23
/// <returns></returns>24
public int GetLength()25
{26
Node<T> p = head;27
int len = 0;28
while (p != null)29
{30
++len;31
p = p.Next;32
}33
return len;34
}35
36
/**//// <summary>37
/// 清空操作38
/// </summary>39
public void Clear()40
{41
head = null;42
}43
44
/**//// <summary>45
/// 判断线性表是否为空46
/// </summary>47
/// <returns></returns>48
public bool IsEmpty()49
{50
if (head == null)51
{52
return true;53
}54
else55
{56
return false;57
}58
}59
60
/**//// <summary>61
/// 附加操作,线性表未满，将值为item的新元素添加到末尾62
/// </summary>63
/// <param name="item"></param>64
public void Append(T item)65
{66
Node<T> newNode = new Node<T>(item); //根据元素创建新的节点67
Node<T> node = new Node<T>();68
69
if (head == null)70
{71
head = newNode;72
return;73
}74
node = head;75
while (node.Next != null)76
{77
node = node.Next;78
}79
node.Next = newNode;80
81
}82
83
/**//// <summary>84
/// 寻找节点85
/// </summary>86
/// <param name="i"></param>87
/// <returns></returns>88
public Node<T> FindNode(int i)89
{90
if (IsEmpty())91
{92
Console.Write("List is empty");93
return null;94
}95
if (i < 1)96
{97
Console.Write("Index is error");98
return null;99
}100
Node<T> current = head;101
int j = 1;102
103
while (current.Next != null && j < i)104
{105
++j;106
current = current.Next;107
}108
return current;109
}110
111
/**//// <summary>112
/// 插入操作,在第i个节点前面插入item113
/// </summary>114
/// <param name="item"></param>115
/// <param name="i"></param>116
public void Insert(T item, int i)117
{118
Node<T> newNode = new Node<T>(item);119
Node<T> node = new Node<T>();120
Node<T> current = FindNode(i);121
if (current != null)122
{123
node = current; //对目标节点备份124
newNode.Next = current;125
node.Next = newNode;126
}127
}128
129
/**//// <summary>130
/// 插入操作,在第i个节点后面插入item131
/// </summary>132
/// <param name="item"></param>133
/// <param name="i"></param>134
public void InsertBack(T item, int i)135
{136
Node<T> newNode = new Node<T>(item);137
Node<T> current = FindNode(i);138
if (current != null)139
{140
newNode.Next = current.Next;141
current.Next = newNode;142
}143
}144
145
/**//// <summary>146
/// 删除操作147
/// </summary>148
/// <param name="i"></param>149
/// <returns></returns>150
public T Delete(int i)151
{152
Node<T> current = FindNode(i);153
Node<T> node = new Node<T>();154
if (current != null)155
{156
node = current; //对目标节点备份157
node.Next = current.Next;158
return current.Data;159
}160
else161
{162
Console.Write("the node is not exist!");163
return default(T);164
}165
}166
167
/**//// <summary>168
/// 去表元169
/// </summary>170
/// <param name="i"></param>171
/// <returns></returns>172
public T GetElem(int i)173
{174
Node<T> current = FindNode(i);175
176
if (current != null)177
{178
return current.Data;179
}180
else181
{182
Console.Write("the node is not exist!");183
return default(T);184
}185
}186
187
/**//// <summary>188
/// 按值查找189
/// </summary>190
/// <param name="value"></param>191
/// <returns></returns>192
public int Locate(T value)193
{194
if (IsEmpty())195
{196
Console.WriteLine("List is Empty!");197
return -1;198
}199
Node<T> current = new Node<T>();200
current = head;201
int i = 1;202
while (current.Next != null && !current.Data.Equals(value))203
{204
current = current.Next;205
++i;206
}207
return i;208
}209
}碰到的问题：1 方法参数为int类型，改用object类型碰到一些问题，查找节点的时候，遍历整个链表，如何对比参数节点
对比参数会不会影响算法的时间复杂度
2 append，insert，insertback方法本质上都是插入操作，有没有更好的方法实现
代码没有经过测试，有兴趣的朋友可以试试，有问题，告知一下！
