栈

栈是一种后进先出的数据结构，下面给出3种实现：静态数组，动态数组、单链表

1、静态数组实现栈

#include <stdio.h>
#define type int
#define max  5


type array[max];
int top=-1;


void push(type);


type pop(void);


type retop();


int isempty();


int isfull();


void static_stackprint()
{
int i;
for(i=0;i<=top;i++)
printf("%d%c",array[i],i==top?'\n':' ');
}
int main()
{
push(1);
push(2);
push(3);
push(4);
push(5);
push(6);
static_stackprint();
printf("pop:%d\n",pop());
printf("pop:%d\n",pop());
static_stackprint();


return 0;
}


int isfull()
{
if(top+1==max)
return 1;
else
return 0;
}


int isempty()
{
if(top==-1)
return 1;
else
return 0;
}


void push(type value)
{
if(!isfull())
{
array[++top]=value;
printf("%d insert successfully\n",value);
}
else
printf("stack is full\n");
}


type pop(void)
{
if(!isempty())
{
return array[top--];
}
else
perror("stack is empty!\n");
}


type retop()
{
if(!isempty())
return array[top];
else
perror("stack is empty!\n");
}

2、动态数组实现

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#define type int




static type *array;
int top=-1;


void push(type);


void pop();


type retop();


int isempty();


void stack_print();


void destroy()
{
assert(top!=-1);
free(array);
array=NULL;
}
int main()
{
push(1);
push(6);
push(3);
push(2);
push(5);
stack_print();
printf("-------------\n");
pop();
pop();
stack_print();
printf("-------------\n");
printf("%d\n",retop());


destroy();
return 0;
}


int isempty()
{
return top==-1?1:0 ;
}


void push(type value)
{
array=(type*)realloc(array,(++top+1)*sizeof(type));
if(array==NULL)
{
perror("realloc faiture\n");
top--;
return ;
}


array[top]=value;
return ;
}


void stack_print()
{
int i;
for(i=0;i<=top;i++)
printf("%d%c",array[i],i==top?'\n':' ');
}


void pop()
{
if(!isempty())
{
array=(type*)realloc(array,(--top+1)*sizeof(type));
if(array==NULL){
perror("realloc failture\n");
top++;
return ;}


return ;
}
}


type retop()
{
if(!isempty())
return array[top];
}

3、单链表实现

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>


#define type int
typedef struct stacknode{
type data;
struct stacknode * next;
}stacknode;


static struct stacknode * stack;


void push(type);


void pop();


type retop();


int isempty();


void destroy();


void stack_print();


int main()
{
push(5);
push(3);
push(4);
push(2);
push(1);
stack_print();
printf("---------------------\n");
pop();
pop();
stack_print();
printf("---------------------\n");
printf("%d\n",retop());
destroy();
return 0;
}


int isempty()
{
return stack==NULL?1:0 ;
}


void push(type value)
{
struct stacknode * newd;
newd=(stacknode *)malloc(sizeof(struct stacknode));
assert(newd!=NULL);
newd->data=value;
newd->next=stack;
stack=newd;
}


void stack_print()
{
struct stacknode *cur=stack;
assert(!isempty());
while(cur!=NULL){
printf("%d%c",cur->data,cur->next==NULL?'\n':' ');
cur=cur->next;}
}


void pop()
{
struct stacknode * cur;
assert(!isempty());
cur=stack;
stack=cur->next;
free(cur);
}


type retop()
{
return stack->data;
}


void destroy()
{
while(!isempty())
{
pop();
}
}