参考 http://www.cnblogs.com/java06/archive/2012/10/16/3122428.html
1，顺序栈
定义栈：
1 #define stacksize 1000; 2 typedef int datatype; 3 4 struct seqstack 5 { 6 datatype data[stacksize]; 7 int top; 8 };
置栈空：
1 void initstack(struct seqstack *s) 2 { 3 s -> top = -1; 4 }
判断栈空：
1 int stackempty(struct seqstack *s) 2 { 3 int flag; 4 5 flag = (s -> top == -1)? 1 : 0; //此处未用if 6 7 return flag; 8 }
入栈：
1 void push(struct seqstack *s,x) 2 { 3 s -> top ++; 4 if stackfull; //伪 5 exit("stack overflow "); //数组溢出 6 7 8 s -> data[s -> top] = x; 9 }
2，链栈
定义栈：
1 typedef struct stacknode 2 { 3 datatype data; 4 struct stacknode *next; 5 }stacknode; 6 7 typedef struct 8 { 9 stacknode *top; 10 }linkstack;
置空：
1 void initstack(linkstack *s) 2 { 3 s -> top = NULL; 4 }
判栈空：
1 void initstack(linkstack *s) 2 { 3 s -> top = NULL; 4 }
入栈:
1 void push(linkstack *s, datatype x) 2 { 3 struct stacknode *p; 4 p = malloc(sizeof(struct stacknode)); 5 p -> data = x; 6 p -> next = s -> top; 7 s -> top = p; 8 }
出栈：
1 datatype pop(linkstack *s) 2 { 3 datatype x; 4 struct stacknode *p = s -> top; 5 if(stackempty(s)) 6 exit("stack is empty! "); 7 x = p -> data; 8 s -> top = p -> next; 9 free(p); 10 return x; 11 }
取栈顶：
1 datatype stacktop(linkstack *s) 2 { 3 if(stackempty(s)) 4 exit("stack is empty! "); 5 return s -> top -> data; 6 }