【数据结构之链栈的基本运算】

链栈的类型：

<pre name="code" class="java">typedef struct stacknode{
		DataType data
		struct stacknode *next
	}StackNode;
	
	typedef struct{
		StackNode *top;//栈顶指针
	}LinkStack;

<pre name="code" class="java">public class LinkStack {
	
	//(1)置栈空
	void InitStack(LinkStack *S){
		S->top = null;
	}
	
	//(2)判断栈空
	int StackEmpty(LinkStack *S){
		return S->top == null;
	}
	
	//(3)进栈
	void push(LinkStack *S,DataType x){
		//将元素x插入链栈头部
		StackNode *p = (StackNode *)malloc(sizeof(StackNode));
	}
	
	//(4)退栈
	DataType Pop(LinkStack *S){
		DataType x;
		StackNode *p = S->top;//保存栈顶指针;
		if(StackEmpty(S)){
			Error("Stack underflow");//下溢
		}
		x = p->data;
		S->top = p->next;//将栈顶指针下移
		free(p);
		return x;
	}
	//(5)取栈顶元素
	DataType Pop(LinkStack *S){
		if(StackEmpty(S)){
			Error("Stack is empty");
		}
		return S->top->data;
	}
	
	
}