利用二叉樹求解表示式的值
阿新 • • 發佈：2019-01-06
#include<stdio.h>
#include<stdlib.h>
#define LIST_INIT_SIZE 100
#define LISTINCREMENT 10
#define STACK_INIT_SIZE 100
#define STACKINCREMENT 10
typedef char Elemtype;
typedef struct{
Elemtype *elem;
int length;
int listsize;
}SqList;
typedef char TElemtype;
typedef struct BiTNode{
TElemtype data;
struct BiTNode *lchild,*rchild;
}BiTNode,*BiTree;
typedef char SElemtype;
typedef struct{
SElemtype *base;
SElemtype *top;
int stacksize;
}SqStack;
#include"operation.h"
main()
{
SqList L;BiTree T;
InitBiTree(T);
InitList(L);
printf("請輸入要操作的算術表示式:");
while((L.elem[L.length]=getchar())!='\n')
{
if(L.length+1>=L.listsize)
{
L.elem=(Elemtype *)realloc(L.elem,
(L.listsize+LISTINCREMENT)*sizeof(Elemtype));
if(!L.elem)exit(-2);
L.listsize+=LISTINCREMENT;
}
L.length++;
}
T=predicate(L,0,L.length);
putchar(10);
printf("前序遍歷:");
PreOrderTraverse(T);
putchar(10);
putchar(10);
printf("中序遍歷:");
InOrderTraverse(T);
putchar(10);
putchar(10);
printf("後序遍歷:");
PostOrderTraverse(T);
putchar(10);
SqStack S;
InitStack(S);
calculate(T,S);
putchar(10);
int result=*S.base;
printf("result=%d",result);
return 0;
}
/*~~~~~~~~~~~~~~~~~~*/
void InitBiTree(BiTree &T) //初始化二叉樹T
{
T=(BiTree)malloc(sizeof(BiTNode));
if(!T)exit(-2);
}
BiTNode* predicate(SqList &L,int frist,int last) //還要考慮小括號在最外層的情況
{
BiTree T1;
if(last-frist==1)
{
BiTree Ty;
InitBiTree(Ty);
Ty->data=L.elem[frist];
Ty->lchild=NULL;
Ty->rchild=NULL;
return Ty;
}
int flag=0,jt=0,ct=0,t=0;
for(int i=frist;i<last;i++)
{
if(L.elem[i]=='(')flag++;
else if(L.elem[i]==')')flag--;
if(flag==0){
if(L.elem[i]=='+'||L.elem[i]=='-')
jt=i;
else if(L.elem[i]=='*'||L.elem[i]=='/')
ct=i;
}
}
if((ct==0)&&(jt==0))
T1=predicate(L,frist+1,last-1);
else{
if(jt>0)t=jt;
else if(ct>0)t=ct;
InitBiTree(T1);
T1->data=L.elem[t];
T1->lchild=predicate(L,frist,t);
T1->rchild=predicate(L,t+1,last);
}
return T1;
}
void InitList(SqList &L)
{
L.elem = (Elemtype *)malloc(LIST_INIT_SIZE*sizeof(Elemtype));
if(!L.elem)exit(-2);
L.length=0;
L.listsize=LIST_INIT_SIZE;
}
void PreOrderTraverse (BiTree T) //先序遍歷二叉樹T
{
if(T==NULL)
{
return;
}
else
{ printf("%c ",T->data);
PreOrderTraverse (T->lchild);
PreOrderTraverse (T->rchild);
}
}
void InOrderTraverse (BiTree T) //中序遍歷二叉樹T
{
if(T==NULL)
{
return;
}
else
{
InOrderTraverse (T->lchild);
printf("%c ",T->data);
InOrderTraverse (T->rchild);
}
}
void PostOrderTraverse (BiTree T) //後序遍歷二叉樹T
{
if(T==NULL)
{
return;
}
else
{
PostOrderTraverse (T->lchild);
PostOrderTraverse (T->rchild);
printf("%c ",T->data);
}
}
void InitStack(SqStack &S){ //棧的初始化
S.base = (SElemtype *)malloc(STACK_INIT_SIZE*sizeof(SElemtype));
if(!S.base)exit(-2);
S.top=S.base;
S.stacksize=STACK_INIT_SIZE;
}
void Push(SqStack &S,int e) //入棧
{
if(S.top-S.base>=S.stacksize)
{S.base=(SElemtype *)realloc(S.base,
(S.stacksize+STACKINCREMENT)*sizeof(SElemtype));
if(!S.base)exit(-2);
S.top=S.base+S.stacksize;
S.stacksize+=STACKINCREMENT;
}
*S.top++=e;
}
int Pop(SqStack &S) //出棧
{ int e;
if(S.top==S.base)return 0;
S.top--;
e=*S.top;
return e;
}
void calculate(BiTree T,SqStack &S)
{
if(T==NULL)
{
return;
}
else
{
calculate(T->lchild,S);
calculate(T->rchild,S);
if(T->data!='+'&&T->data!='-'&&T->data!='/'&&T->data!='*')
{
int n=T->data-'0';
Push(S,n);
}
else
{ int a=Pop(S);
int b=Pop(S);
int result=0;
if(T->data=='+')result=b+a;
else if(T->data=='-')result=b-a;
else if(T->data=='/')result=b/a;
else if(T->data=='*')result=b*a;
Push(S,result);
}
}
}