資料結構之鏈式棧
#include<stdio.h> #include<stdlib.h> typedef int Elemtype; typedef struct node //定義結點 { Elemtype data; struct node *up; struct node *down; }Node; typedef struct linkstack //定義棧 { Node *top; Node *bottom; int max; int length; }Linkstack; Linkstack *crea(int max) //生成空棧 { Linkstack *s=(Linkstack *)malloc(sizeof(*s)); s->top=NULL; s->bottom=NULL; s->max=max; s->length=0; return s; }
int isFull(Linkstack *s) //判斷棧是否已滿 { if(s->length==s->max) { return 1; } return 0; }
int isEmpty(Linkstack *s) //判斷是否為空棧 { if(s->length==0) { return 1; } return 0; }
void push(Linkstack *s,Elemtype data) //入棧 { if(isFull(s)) { return ; } s->length++; Node *pnew=(Node *)malloc(sizeof(*pnew)); pnew->data=data; pnew->up=NULL; pnew->down=NULL; // if(isEmpty(s)) //錯誤！在這之前s->length已經改變！！ if(s->top==NULL) { s->top=pnew; s->bottom=pnew; } else { s->top->up=pnew; pnew->down=s->top; s->top=pnew; } }
/****************************************** 出棧方法1： Description: //這裡不要用成指標函式！！！ */
Elemtype pop(Linkstack *s) //出棧 { if(isEmpty(s)) { return ; } s->length--; Elemtype data=s->top->data; Node *p=s->top; if(s->top==s->bottom) { s->bottom=NULL; s->top=NULL; free(p); } else { s->top=s->top->down; s->top->up=NULL; p->down=NULL; free(p); } return data; }
/************************************** ****** 鏈式棧輸出後必須釋放空間？？？ 並不是，不釋放掉，下次出棧入棧也沒有影響， 但是這塊空間會被一直佔著，影響電腦執行！！！ **/
/*************************************************** 出棧方法2；
**/ /* Elemtype pop(Linkstack *s) //出棧 { if(isEmpty(s)) { return ; } s->length--; Elemtype data=s->top->data; s->top=s->top->down; return data; } */
/**直接使用棧頂的數*****/ Elemtype getHead(Linkstack *s) { return s->top->data; }
/********************************************************** 將棧初始化； **********/ void clearstack(Linkstack *s) { Node *p=s->top; while(p) { s->top=s->top->down; free(p); //釋放棧頂所佔空間 p=s->top; } s->top=NULL; s->bottom=NULL; s->length=0; } /********************************************* 銷燬棧 ***********/ void destroystack(Linkstack *s) { if(s)//若不是空棧 { clearstack(s); //呼叫初始化函式將其初始化 } free(s); //釋放空棧所佔記憶體； }
int main() { Linkstack *s=crea(10); push(s,3); push(s,4); push(s,5); //入棧 Elemtype a=pop(s); //出棧 printf("%d\n",a); //5 a=pop(s); printf("%d\n",a); //4 a=pop(s); printf("%d\n",a); //3 a=pop(s); printf("%d\n",a); //1 a=pop(s); printf("%d\n",a); //1 push(s,10); push(s,40); push(s,50); a=pop(s); printf("%d\n",a); //50 a=getHead(s); //直接去棧頂的數 printf("zd=%d\n",a); //zd=40 直接去棧頂的數 a=pop(s); printf("%d\n",a); //40 a=pop(s); printf("%d\n",a); //10 clearstack(s); //將棧初始化 a=pop(s); //讓空棧出棧 printf("%d\n",a); //1 destroystack(s); return 0; }