C语言—栈

栈的操作：进栈和出栈

 #include "stdafx.h"
 #include "stack.h"
 #define maxsize  20
 typedef int Elemtype;

 /*顺序存储—数组形式*/
 struct stack
 {
     int data[maxsize];
     int top;
 };

 void init(struct stack *ps)
 {
     ps->top = -;
 }

 void init2(struct Doublestack * ps)
 {
     ps->top1 = -;
     ps->top2 =maxsize;
 }

 void  print(int a[],int len)
 {
     int i;
     // len = sizeof(a) / sizeof(a[0]);这样子你得不到长度的，此时a退化为了指针
     for (i = ; i <= len - ; i++)
     {
         printf("%d\n", a[i]);
     }
 }
 int push(struct stack * s, int e)
 {
     if (s->top == maxsize - )
         return -;
     s->data[++s->top] = e;
     return ;
 }

 Elemtype  pop(struct stack *s)
 {
     int n;
     if (s->top == )
         return -;
     n = s->data[s->top--];

     return n;
 }

 //两栈共享
 struct Doublestack
 {
     int data[maxsize];
     int top1;
     int top2;
 };

 int push_two(struct Doublestack *s, int e, int stackflag)
 {
     if (s->top1 == s->top2 - )  //full stack
         return -;
     if (stackflag == )
     {
         s->data[++s->top1] = e;
     }
     else if (stackflag == )
     {
         s->data[--s->top2] = e;
     }
     return ;
 }
 Elemtype pop_two(struct Doublestack *s,  int stackflag)
 {
     int n;
     if (stackflag == )
     {
         if (s->top1 == -)  //s1 empty
             return -;
         n = s->data[s->top1--];
     }
     else if (stackflag == )
     {
         if (s->top2 ==maxsize)  //s2 empty
             return -;
         n = s->data[s->top2++];
     }
     //printf("%d\n", n);
     return n;
 }

主函数

 #include "stdafx.h"
 #include  "link.h"
 #include "stack.h"

 int main()
 {

     /*stack_test*/
     //struct stack s;
     //struct stack *ps = &s;
     //init(ps);

     struct Doublestack s;
     struct Doublestack * ps = &s;
     init2(ps);
     int e = ;
     int n;
     //push( ps,  e);
     //push(ps, 2);
     //print(ps->data,2);
     //n = pop(ps);
     //printf("%d\n", n);

     push_two(ps, e,);
     push_two(ps, , );
     print(ps->data, );
      n=pop_two(ps,);
     printf("n =%d\n", n);

     system("pause");

 }