中缀表达式转后缀表达式并计算结果(C语言版)(共8页)

1、精选优质文档-倾情为你奉上中缀表达式转后缀表达式中缀表达式转后缀表达式的规则。1.遇到操作数：直接输入到后缀表达式栈2.遇到运算符，直接入操作符栈3.遇到左括号：直接将其入栈4.遇到右括号：执行出栈操作，并将出栈的元素输出，直到弹出栈的是左括号，左括号不输出。5.遇到其他运算符：加减乘除：弹出所有优先级大于或者等于该运算符的栈顶元素，然后将该运算符入栈6.最终将操作符栈中的元素依次出栈，输出到后缀表达式栈。以下是自己写的代码。亲测没有问题。（模拟一个计算器，可以带括号，中间可以空格，只支持整数输入，但是输出结果精确到小数后6位）#include "stdio.h"#defi

2、ne MAX_LEN 100typedef struct calunsigned char isOper;/是否是操作数 1，操作符 0.操作数double Num;/值。或者是操作符的ASCII值STRUCT_CAL;#define IS_NUM 0x00#define IS_OPER0x01STRUCT_CAL stackCalMAX_LEN;STRUCT_CAL stackCalBackMAX_LEN;unsigned char topCal;char stackOperMAX_LEN;unsigned char topOper;/* 堆栈初始化*/void stackInit(void

3、)int i;for(i=0;i<MAX_LEN;i+)stackCali.isOper = 0;stackCali.Num = 0;stackOperi = 0;topCal = topOper = 0;/* 返回堆栈的栈顶，返回后栈顶减一*/STRUCT_CAL * stackCalPop(void)if(topCal = 0)return (STRUCT_CAL *)0;return stackCal+(-topCal);/* 计算表达式入栈*/void stackCalPush(double num, unsigned char isOper)if(topCal>=MAX_

4、LEN)return;stackCaltopCal.Num = num;stackCaltopCal.isOper= isOper;topCal+;/* 操作符出栈*/char stackOperPop(void)if(topOper = 0)return 0;return stackOper-topOper;/* 操作符入栈*/void stackOperPush(char oper)if(topOper >=MAX_LEN)return;stackOpertopOper+ = oper;/*比较两个 sour sour1 的优先级*1 sour >= sour1 直接入操作符栈

5、*0 sour < sour1 直接入计算表达式栈*/unsigned char comparPrior(char sour, char sour1)if(sour ='0' |sour1 = '0') return 1;switch(sour)case '+':case '-':if(sour1 = '*' |sour1 = '/'|sour1 = '+' |sour1 = '-' )return 0;elsereturn 1;break;case '

6、*':case '/':if(sour1 = '*' |sour1 = '/'|sour1 = '+' |sour1 = '-'|sour1 = '(')return 1;elsereturn 0;break;default:return 1;break;/* 将输入的字符串转换为栈*/void StrToCal(char *pStr)int tmpNum = 0;char tmpOper;char islastNum = 0;/判断上一个字符是什么。如果是符号，现在碰到-，那么数字就是负数

7、char isNumNegative = 0;while(*pStr != '0')switch(*pStr)case '+':while(comparPrior('+',stackOpertopOper-1) = 0)stackCalPush(stackOperPop(), IS_OPER);if(topOper<1)break;stackOperPush('+');pStr+;islastNum = 0;break;case '-':if(islastNum = 0) /如果上一个字符是 操作符，那么接下

8、来的数字是负数isNumNegative = 1;/ 1代表 是负数pStr+;break;while(comparPrior('-',stackOpertopOper-1) = 0)stackCalPush(stackOperPop(), IS_OPER);if(topOper<1)break;stackOperPush('-');pStr+;islastNum = 0;break;case '*':while(comparPrior('*',stackOpertopOper-1) = 0)stackCalPush(sta

9、ckOperPop(), IS_OPER);if(topOper<1)break;stackOperPush('*');pStr+;islastNum = 0;break;case '/':while(comparPrior('/',stackOpertopOper-1) = 0)stackCalPush(stackOperPop(), IS_OPER);if(topOper<1)break;stackOperPush('/');pStr+;islastNum = 0;break;case '(':st

10、ackOperPush('(');pStr+;islastNum = 0;break;case ')':while(tmpOper = stackOperPop() != '(')stackCalPush(tmpOper, IS_OPER);pStr+;islastNum = 0;break;case '0':case '1':case '2':case '3':case '4':case '5':case '6':case '

11、7':case '8':case '9':while(*pStr >='0' )&& (*pStr <='9')tmpNum = tmpNum *10 +*(pStr+) - '0'if(isNumNegative)isNumNegative = 0;tmpNum = -tmpNum;stackCalPush(tmpNum, IS_NUM);tmpNum = 0;islastNum = 1;break;case ' ':pStr+;break;default:pS

12、tr+;break;while(topOper) /如果最后操作符栈还有数据，直接入计算栈stackCalPush(stackOperPop(), IS_OPER);/* 显示转换后的后缀表达式，用于调试，看转换是否正确*/void dispCalc(void)int i = 0;printf("n");for(i = 0;i<topCal;i+)if(stackCali.isOper = IS_NUM)printf("%d",(int)stackCali.Num);else if(stackCali.isOper = IS_OPER)printf

13、("%c",(char)stackCali.Num);/* 计算后缀表达式的计算结果*/void suffixExpression(void)int i = 0;int tmpTop;double num1,num2;for(i = 0;i<topCal;i+)stackCalBacki = stackCali;i = 0;tmpTop = topCal;topCal = 0;while(1)if(stackCalBacki.isOper = IS_OPER)num1 = stackCalPop()->Num;num2 = stackCalPop()->N

14、um;switch(char)stackCalBacki.Num)case '+':stackCalPush(num2+num1, IS_NUM);break;case '-':stackCalPush(num2-num1, IS_NUM);break;case '*':stackCalPush(num2*num1, IS_NUM);break;case '/':stackCalPush(int)num2/num1, IS_NUM);break;default :break;elsestackCalPush(stackCalBacki.Num, IS_NUM);i+;if(i>=tmpTop) break;printf("nThe result is :