数据结构-C语言实现-链栈

 1 #include <stdio.h>
 2 #include <stdlib.h>
 3 #include <ctype.h>
 4 #include <string.h>
 5 typedef int ElemType;
 6 typedef struct item{
 7   ElemType items;//数据项
 8   struct item *next;//指向下一个数据项的指针
 9 }item;
10 typedef struct stack{
11   item *top;//总是指向栈顶(即最后一个数据项的指针)
12   int length;//当前栈的长度(存储数据项的个数)
13 }stack;
14 stack * initstack(){
15   stack * stacks=(stack *)malloc(sizeof(stack));
16   stacks->top=NULL;
17   stacks->length=0;//长度初始化
18   return stacks;
19 }
20 void pop(stack * stacks){
21   item *p = stacks->top;
22   printf("%d已弹出!\n",stacks->top->items);
23   stacks->top=stacks->top->next;
24   free(p);
25 }
26 void push(stack * stacks){
27   printf("输入你想添加的整数:\n");
28   ElemType a;
29   scanf("%d",&a);
30   item *p=(item *)malloc(sizeof(item));
31   p->items=a;
32   p->next=stacks->top;
33   stacks->top=p;
34   stacks->length++;
35 }
36 void display(stack * stacks){
37   if(stacks->top){
38     item *p=stacks->top;//获取栈顶元素
39     printf("以下为数据,由新到旧:\n");
40     while(p){
41     printf("%d ",p->items);
42     p=p->next;
43     }
44     printf("\n");
45   }
46   else
47   printf("栈为空!\n");
48 }
49 void menu(){
50   printf("键入以下选项以操作,ctrl+z退出\nA:添加数据\nB:弹出数据\nC:打印数据\n");
51 }
52 void main(){
53   stack *stacks=initstack();
54   menu();
55   char ch;
56   while((ch=getchar())!=EOF){
57     setbuf(stdin,NULL);
58     switch (toupper(ch)){
59       case ‘A‘: push(stacks);break;
60       case ‘B‘: pop(stacks);break;
61       case ‘C‘: display(stacks);break;
62     }
63   menu();
64   setbuf(stdin,NULL);
65   }
66 }