C语言实现二叉树的建立、遍历以及表达式的计算
实现代码
#include <stdio.h>
#include <stdlib.h>
#include <malloc.h>
#include <ctype.h>
#define StackInitSize 100
#define max 20
#define isNum 1
#define isCha 0
#define lenNum sizeof(struct nodeNum)
#define lenCha sizeof(struct nodeCha)
#define lenBiTree sizeof(struct biTreeNode)
//操作数节点元素
struct nodeNum{
int number;
};
//操作符节点元素
struct nodeCha{
char ch;
};
//共用体
typedef union demo{
int number;
char cha;
}Demo;
//二叉树节点
struct biTreeNode{
int flag;
Demo useUnion;
struct biTreeNode *lchild;
struct biTreeNode *rchild;
};
//二叉树节点栈 ！会初始化两个二叉树节点栈！
struct biTreeStack{
struct biTreeNode *base;
struct biTreeNode *top;
int stackSize;
};
//操作数栈
struct numStack{
struct nodeNum *base;
struct nodeNum *top;
int stackSize;
};
//操作符栈
struct chaStack{
struct nodeCha *base;
struct nodeCha *top;
int stackSize;
};
//初始化二叉树栈
void biTreeInitStack(struct biTreeStack *stack0)
{
stack0->base = (struct biTreeNode *)malloc(StackInitSize * lenBiTree);
if(!stack0->base)
{
printf("没有足够空间!\n退出程序！\n");
exit(0);
}
stack0->top = stack0->base;
stack0->stackSize = StackInitSize;
}
//初始化操作数栈
void numInitStack(struct numStack *stack1)
{
stack1->base = (struct nodeNum *)malloc(StackInitSize * lenNum);
if(!stack1->base)
{
printf("没有足够空间!\n退出程序！\n");
exit(0);
}
stack1->top = stack1->base;
stack1->stackSize = StackInitSize;
}
//初始化操作符栈
void chaInitStack(struct chaStack *stack2)
{
stack2->base = (struct nodeCha *)malloc(StackInitSize * lenCha);
if(!stack2->base)
{
printf("没有足够空间!\n退出程序！\n");
exit(0);
}
stack2->top = stack2->base;
stack2->stackSize = StackInitSize;
}
//压入操作符
void chaPush(struct chaStack *stack3,char ch)
{
if(stack3->top - stack3->base >= stack3->stackSize)
{
printf("栈满！\n退出程序！\n");
exit(0);
}
stack3->top->ch = ch;
stack3->top++;
}
//压入操作数
void numPush(struct numStack *stack4,int number)
{
if(stack4->top - stack4->base >= stack4->stackSize)
{
printf("栈满！\n退出程序！\n");
exit(0);
}
stack4->top->number = number;
stack4->top++;
}
//压入栈节点
void biTreeNodePush(struct biTreeStack *curBiTree,struct biTreeNode curTreeNode)
{
if(curBiTree->top - curBiTree->base >= curBiTree->stackSize)
{
printf("栈满！\n退出程序！\n");
exit(0);
}
*curBiTree->top = curTreeNode;
curBiTree->top++;
}
//弹出栈节点
//因为是对指针进行操作，在弹完栈后再往里压栈就会覆盖原来的内容，所以就会出现问题！！！！！！
struct biTreeNode *biTreeNodePop(struct biTreeStack *curBiTree)
{
if(curBiTree->top != curBiTree->base)
{
curBiTree->top--;
return curBiTree->top;
}
else
{
printf("栈已空！\n退出程序！\n");
exit(0);
}
}
void recoverPtr(struct biTreeStack *curBiTree)
{
curBiTree->top++;
curBiTree->top++;
}
//弹出操作符
char chaPop(struct chaStack *stack5)
{
if(stack5->top != stack5->base)
{
stack5->top--;
return stack5->top->ch;
}
else
{
printf("栈已空！\n退出程序！\n");
exit(0);
}
}
//弹出操作数
int numPop(struct numStack *stack6)
{
if(stack6->top != stack6->base)
{
stack6->top--;
return stack6->top->number;
}
else
{
printf("栈已空！\n退出程序！\n");
exit(0);
}
}
//运算符栈取顶
char chaGetTop(struct chaStack stack7)
{
if(stack7.top >= stack7.base)
{
stack7.top--;
return stack7.top->ch;
}
else
{
printf("栈已空！\n退出程序！\n");
exit(0);
}
}
//运算数栈取顶
int numGetTop(struct numStack stack8)
{
if(stack8.top >= stack8.base)
{
stack8.top--;
return stack8.top->number;
}
else
{
printf("栈已空！\n退出程序！\n");
exit(0);
}
}
//判断并返回算符间的优先关系
char Precede(char ch1,char ch2)
{
char ch = ' ';
switch(ch1)
{
case '$':
if('+' == ch2||'-' == ch2||'*' == ch2||'/' == ch2||'(' == ch2)
{
ch = '<';
}
else if(')' == ch2)
{
printf("输入有误！\n退出程序！\n");
exit(0);
}
else if('$' == ch2)
{
ch = '=';
}
break;
case ')':
if('+' == ch2||'-' == ch2||'*' == ch2||'/' == ch2||')' == ch2||'$' == ch2)
{
ch = '>';
}
else if('(' == ch2)
{
printf("输入有误！\n退出程序！\n");
exit(0);
}
break;
case '(':
if('+' == ch2||'-' == ch2||'*' == ch2||'/' == ch2||'(' == ch2)
{
ch = '<';
}
else if(')' == ch2)
{
ch = '=';
}
else if('$' == ch2)
{
printf("输入有误！\n退出程序！\n");
exit(0);
}
break;
case '/':
if('+' == ch2||'-' == ch2||'*' == ch2||'/' == ch2||')' == ch2||'$' == ch2)
{
ch = '>';
}
else if('(' == ch2)
{
ch = '<';
}
break;
case '*':
if('+' == ch2||'-' == ch2||'*' == ch2||'/' == ch2||')' == ch2||'$' == ch2)
{
ch = '>';
}
else if('(' == ch2)
{
ch = '<';
}
break;
case '-':
if('+' == ch2||'-' == ch2||')' == ch2||'$' == ch2)
{
ch = '>';
}
else if('*' == ch2||'/' == ch2||'(' == ch2)
{
ch = '<';
}
break;
case '+':
if('+' == ch2||'-' == ch2||')' == ch2||'$' == ch2)
{
ch = '>';
}
else if('*' == ch2||'/' == ch2||'(' == ch2)
{
ch = '<';
}
break;
default:
{
printf("非法输入！\n退出程序！\n");
exit(0);
}
}
return ch;
}
//将弹出的数进行计算
int Operate(int numa,char ch,int numb)
{
int number = 0;
switch(ch)
{
case '+':
number = numa + numb;
break;
case '-':
number = numa - numb;
break;
case '*':
number = numa * numb;
break;
case '/':
number = numa / numb;
break;
}
return number;
}
//先序遍历二叉树
void preOrder(struct biTreeNode *biTree)
{
if(biTree->flag == isNum)
{
printf("%d ",biTree->useUnion.number);
}
else if(biTree->flag == isCha)
{
printf("%c ",biTree->useUnion.cha);
}
if(biTree->lchild != NULL) preOrder(biTree->lchild);
if(biTree->rchild != NULL) preOrder(biTree->rchild);
}
//后序遍历二叉树
void aftOrder(struct biTreeNode *biTree)
{
if(biTree->lchild != NULL) aftOrder(biTree->lchild);
if(biTree->rchild != NULL) aftOrder(biTree->rchild);
if(biTree->flag == isNum)
{
printf("%d ",biTree->useUnion.number);
}
else if(biTree->flag == isCha)
{
printf("%c ",biTree->useUnion.cha);
}
}
//显示二叉树
void outPutBiTree(struct biTreeNode *biTree)
{
if(biTree != NULL)
{
if(biTree->flag == isNum)
{
printf("%d ",biTree->useUnion.number);
}
else if(biTree->flag == isCha)
{
printf("%c ",biTree->useUnion.cha);
}
}
if(biTree->lchild != NULL)
{
printf("(");
outPutBiTree(biTree->lchild);
printf(",");
}
if(biTree->rchild != NULL)
{
outPutBiTree(biTree->rchild);
printf(")");
}
}
//表达式求值并创建二叉树
int doEvaluateExpression()
{
char ch,x,the;
int numa,numb;
int count;
int i,temp;
long number,num[max];
struct numStack opnd;
struct chaStack optr;
struct biTreeNode tempTreeNode,*finTreeNode,*treeNode_1,*treeNode_2;
struct biTreeStack binaryTree,binaryTree_0;
numInitStack(&opnd);//初始化操作数栈
chaInitStack(&optr);//初始化操作符栈
biTreeInitStack(&binaryTree);//初始化二叉树节点栈
biTreeInitStack(&binaryTree_0);//初始化二叉树节点栈副本
chaPush(&optr,'$');
printf("请输入表达式(以$号结束):\n");
ch = getchar();
//如果产生矛盾，可以尝试将所有数据一次性读入一个数组里，
//进而可以通过对数组下标进行操作而达到目的，
//或者使用ungetc()函数
while(!(ch == '$' && chaGetTop(optr) == '$'))
{
if(isdigit(ch)) //如果是数字就进运算数栈
{
count = 0;
number = 0;
while(isdigit(ch))//如果getchar()得到的是数字,则连续读
{
count++;
num[count-1] = ch-48;
ch = getchar();
}
temp = count;
for(i = 0; i < count; i++)//判断数字有几位
{
temp--;
number += num[i] * pow(10,temp);
}
numPush(&opnd,number);
tempTreeNode.flag = isNum;
tempTreeNode.useUnion.number = number;
tempTreeNode.rchild = NULL;
tempTreeNode.lchild = NULL;
biTreeNodePush(&binaryTree,tempTreeNode);
}
else
{
//若无限循环则说明 ch 可能为空了
switch(Precede(chaGetTop(optr),ch))//判断优先级
{
case '<': //栈顶元素优先权低
chaPush(&optr,ch);
ch = getchar();
break;
case '=': //脱括号并接收下一个字符
x = chaPop(&optr);
ch = getchar();
break;
case '>': //退栈并将运算结果入栈
the = chaPop(&optr);
numb = numPop(&opnd);
numa = numPop(&opnd);
numPush(&opnd,Operate(numa,the,numb));
tempTreeNode.flag = isCha;
tempTreeNode.useUnion.cha = the;
treeNode_1 = biTreeNodePop(&binaryTree);
treeNode_2 = biTreeNodePop(&binaryTree);
biTreeNodePush(&binaryTree_0,*treeNode_1);//弹出的内容转存到另一个节点栈里，避免覆盖
biTreeNodePush(&binaryTree_0,*treeNode_2);//弹出的内容转存到另一个节点栈里，避免覆盖
tempTreeNode.lchild = biTreeNodePop(&binaryTree_0);
tempTreeNode.rchild = biTreeNodePop(&binaryTree_0);
recoverPtr(&binaryTree_0);//恢复副本栈里的指针指向
biTreeNodePush(&binaryTree,tempTreeNode);
break;
default:
printf("其他字符！\n退出程序！\n");
exit(0);
break;
}
}
}
finTreeNode = biTreeNodePop(&binaryTree);
printf("\n显示表达式树(广义表)为:\n");
outPutBiTree(finTreeNode);
printf("\n\n二叉树先序遍历:\n");
preOrder(finTreeNode);//先序遍历
printf("\n\n二叉树后序遍历:\n");
aftOrder(finTreeNode);
return numGetTop(opnd);
}
int main()
{
printf("\n\n计算结果是：%d\n",doEvaluateExpression());
return 0;
}
测试结果
几年前写的代码了，今天整理了下，居然发现个bug：
作者：Standby — 一生热爱名山大川、草原沙漠，还有我们小郭宝贝！
出处：http://www.cnblogs.com/standby/
本文版权归作者和博客园共有，欢迎转载，但未经作者同意必须保留此段声明，且在文章页面明显位置给出原文连接，否则保留追究法律责任的权利。
出处：http://www.cnblogs.com/standby/
本文版权归作者和博客园共有，欢迎转载，但未经作者同意必须保留此段声明，且在文章页面明显位置给出原文连接，否则保留追究法律责任的权利。
