数据结构-栈（1）

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顺序栈链式栈

栈是先进后出可以通过顺序表封装一个顺序栈//代码如下

#pragma once//定长的顺序栈//todo   将定长的顺序栈改成泛型//todo   将定长的顺序栈改成不定长#define SIZE 10typedef struct Stack{int elem[SIZE];//void *int top;//栈顶指针，标记当前可以存放数据的下标}Stack,*PStack;void InitStack(PStack ps);//入栈bool Push(PStack ps,int val);bool IsEmpty(PStack ps);//获取栈顶元素的值，但不删除bool GetTop(PStack ps,int *rtval);//获取栈顶元素的值，且删除bool Pop(PStack ps,int *rtval);void Clear(PStack ps);void Destroy(PStack ps);#include <stdio.h>#include <assert.h>#include "stack.h"void InitStack(PStack ps){assert(ps != NULL);ps->top = 0;}static bool IsFull(PStack ps){return ps->top == SIZE;}//入栈bool Push(PStack ps,int val)//O(1){if(IsFull(ps)){return false;}ps->elem[ps->top++] = val;return true;}bool IsEmpty(PStack ps){return ps->top == 0;}//获取栈顶元素的值，但不删除bool GetTop(PStack ps,int *rtval)//O(1){if(IsEmpty(ps)){return false;}*rtval = ps->elem[ps->top - 1];return true;}//获取栈顶元素的值，且删除bool Pop(PStack ps,int *rtval)//O(1){if(IsEmpty(ps)){return false;}*rtval = ps->elem[--ps->top];return true;}void Clear(PStack ps);void Destroy(PStack ps);#include "stack.h"int main(){Stack s;InitStack(&s);for(int i=0;i<15;i++){Push(&s,i);}int tmp;while(!IsEmpty(&s)){Pop(&s,&tmp);printf("%d\n",tmp);}return 0;}

建立一个链式栈通过链式栈把方程改成中缀

#pragma once//链式栈，利用带头节点的单链表实现，栈顶在表头typedef struct SNode{int data;struct SNode *next;//链式栈的栈顶在表头，不需要额外添加栈顶指针}SNode,*PStack;void InitStack(PStack ps);//入栈bool Push(PStack ps,int val);bool IsEmpty(PStack ps);//获取栈顶元素的值，但不删除bool GetTop(PStack ps,int *rtval);//获取栈顶元素的值，且删除bool Pop(PStack ps,int *rtval);void Clear(PStack ps);void Destroy(PStack ps);#pragma once//存放运算符的优先级/*********************************************************************************************************  运算符优先级，数值越小优先级越高*********************************************************************************************************/#define OPERA_PRIO_PLUS_IN            4                                 /*  栈内 +                      */#define OPERA_PRIO_MINUS_IN           4                                 /*  栈内 -                      */#define OPERA_PRIO_MULTIPLY_IN        2                                 /*  栈内 *                      */#define OPERA_PRIO_DIVISION_IN        2                                 /*  栈内 /                      */#define OPERA_PRIO_LEFT_BRACKETS_IN   10                                /*  栈内 (                      */#define OPERA_PRIO_PLUS_OUT           5                                 /*  栈外 +                      */#define OPERA_PRIO_MINUS_OUT          5                                 /*  栈外 -                      */#define OPERA_PRIO_MULTIPLY_OUT       3                                 /*  栈外 *                      */#define OPERA_PRIO_DIVISION_OUT       3                                 /*  栈外 /                      */#define OPERA_PRIO_LEFT_BRACKETS_OUT  1                                 /*  栈外 (                      */#define OPERA_PRIO_RIGHT_BRACKETS_OUT 10                                /*  栈外 )                      */#define OPERA_PRIO_ERR                -1#include <stdio.h>#include <stdlib.h>#include <assert.h>#include "lstack.h"void InitStack(PStack ps){assert(ps != NULL);ps->next = NULL;}//入栈,头插bool Push(PStack ps,int val)//O(1){SNode *p = (SNode *)malloc(sizeof(SNode ));p->data = val;p->next = ps->next;ps->next = p;return true;}bool IsEmpty(PStack ps){return ps->next == NULL;}//获取栈顶元素的值，但不删除bool GetTop(PStack ps,int *rtval)//O(1){if(IsEmpty(ps)){return false;}*rtval = ps->next->data;return true;}//获取栈顶元素的值，且删除bool Pop(PStack ps,int *rtval)//O(1){if(IsEmpty(ps)){return false;}SNode *p = ps->next;ps->next = p->next;*rtval = p->data;free(p);return true;}void Clear(PStack ps){Destroy(ps);}void Destroy(PStack ps){SNode *p;while(ps->next != NULL){p = ps->next;ps->next = p->next;free(p);}}int Priority(char opera, bool InStack){int prio = OPERA_PRIO_ERR;if(InStack){switch(opera){case '+':prio  = OPERA_PRIO_PLUS_IN;break;case '-':prio  = OPERA_PRIO_MINUS_IN;break;case '*':prio  = OPERA_PRIO_MULTIPLY_IN;break;case '/':prio  = OPERA_PRIO_DIVISION_IN;break;case '(':prio  = OPERA_PRIO_LEFT_BRACKETS_IN;break;default:prio = OPERA_PRIO_ERR;break;}}else{switch(opera){case '+':prio  = OPERA_PRIO_PLUS_OUT;break;case '-':prio  = OPERA_PRIO_MINUS_OUT;break;case '*':prio  = OPERA_PRIO_MULTIPLY_OUT;break;case '/':prio  = OPERA_PRIO_DIVISION_OUT;break;case '(':prio  = OPERA_PRIO_LEFT_BRACKETS_OUT;break;case ')':prio  = OPERA_PRIO_RIGHT_BRACKETS_OUT;break;default:prio = OPERA_PRIO_ERR;break;}}return prio;}void MidtoLast(char *last,const char *mid){SNode s;InitStack(&s);int i = 0;//last下标int prioIn;//栈内符号优先级int prioOut;//栈外符号优先级int tmp;while(*mid != '\0'){if(isdigit(*mid)){last[i++] = *mid++;}else //运算符{if(IsEmpty(&s))//栈空{Push(&s,*mid++);}else //栈不空，比较优先级{GetTop(&s,&tmp);prioIn = Priority(tmp,true);prioOut =  Priority(*mid,false);if(prioOut < prioIn)//栈外优先级高，进栈{Push(&s,*mid++);}else if(prioOut > prioIn)//栈外优先级低，出栈{Pop(&s,&tmp);last[i++] = (char)tmp;}else//优先级相等，（）匹配,直接删除{mid++;Pop(&s,&tmp);}}}}while(!IsEmpty(&s)){Pop(&s,&tmp);last[i++] = (char)tmp;}last[i] = '\0';}int main(){char *mid = "3+4*(5-3)/(4-2)";char last[100];MidtoLast(last,mid);printf("%s\n%s\n",mid,last);return 0;}

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