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#include<stdio.h>
#include<stdlib.h>
typedef int ElementType; /*栈元素类型*/
#define SUCCESS 0
#define FAILURE -1
/*定义栈结构*/
typedef struct StackInfo
{
ElementType value; /*栈存储的数据*/
struct StackInfo *next; /*指向栈的下一个元素*/
}StackInfo_st;
/*函数声明*/
StackInfo_st *createStack(void);
int stack_push(StackInfo_st *s,ElementType value);
int stack_pop(StackInfo_st *s,ElementType *value);
int stack_top(StackInfo_st *s,ElementType *value);
int stack_is_empty(StackInfo_st *s);
/*创建栈,外部释放内存*/
StackInfo_st *createStack(void)
{
StackInfo_st *stack = (StackInfo_st *)malloc(sizeof(StackInfo_st));
if(NULL == stack)
{
printf("malloc failed\n");
return NULL;
}
stack->next = NULL;
return stack;
}
/*入栈,0表示成,非0表示出错*/
int stack_push(StackInfo_st *s,ElementType value)
{
StackInfo_st *temp = (StackInfo_st *)malloc(sizeof(StackInfo_st));
if(NULL == temp)
{
printf("malloc failed\n");
return FAILURE;
}
/*将新的节点添加s->next前,使得s->next永远指向栈顶*/
temp->value = value;
temp->next = s->next;/*这一句是指向栈头部,实际上不用也没有问题*/
s->next = temp;
return SUCCESS;
}
/*出栈*/
int stack_pop(StackInfo_st *s,ElementType *value)
{
/*首先判断栈是否为空*/
if(stack_is_empty(s))
return FAILURE;
/*找出栈顶元素*/
*value = s->next->value;
/*保存等下需要free的指针*/
StackInfo_st *temp = s->next;
/*更换栈顶的位置*/
s->next = s->next->next;
/*释放栈顶节点内存*/
if(temp!=NULL)/*先判断指针是否为空*/
free(temp);
temp = NULL;
return SUCCESS;
}
/*访问栈顶元素*/
int stack_top(StackInfo_st *s,ElementType *value)
{
/*首先判断栈是否为空*/
if(stack_is_empty(s))
return FAILURE;
*value = s->next->value;
return SUCCESS;
}
/*判断栈是否为空,空返回1,未空返回0*/
int stack_is_empty(StackInfo_st *s)
{
/*栈顶指针为空,则栈为空*/
return s->next == NULL;
}
int main(void)
{
/*创建栈*/
StackInfo_st *stack = createStack();
/*如果栈为空,则压入元素1*/
if(stack_is_empty(stack))
{
int i = 0;
for(i = 0 ;i< 23;i++)
{
printf("push value %d\n",i);
stack_push(stack,i);
}
}
/*访问栈顶元素*/
int topVal;
stack_top(stack, &topVal);
printf("top value %d\n",topVal);
/*出栈*/
int tm = 0;
for(tm = 0;tm<25;tm++)
{
int popVal;
stack_pop(stack, &popVal);
printf("pop value %d %d\n",tm,popVal);
}
int i = 0;
while(SUCCESS == stack_push(stack,i) && i < 5)
{
i++;
}
printf("top if stack value is %d\n",stack->next->value);
/*最后记得将栈内存都释放,可自己尝试实现*/
return 0;
}