中缀表达式转后缀表达式并计算结果(C语言版)#精选.

1、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 100 typedef 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ASCI值STRUCT_CAL;#define IS_NUM0x00#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(voi

3、d)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(topC

4、al>=MAX_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 >=

5、 sour1 直接入操作符栈*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;b

6、reak;case '*':case '/':if(sour1 = '*' |sour1 = '/'|sour1 = '+' |sour1 = '-'|sour1 = '(') return 1;else return 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

7、是符号，现在碰到-'，那么数字就是负数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(isla

8、stNum = 0) / 如果上一个字符是 操作符，那么接下来的数字是负数 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('*',s

9、tackOpertopOper-1) = 0) stackCalPush(stackOperPop(), 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('/')

10、; pStr+;islastNum = 0; break;case '(': stackOperPush('('); 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 &#

11、39;4': case '5':case '6':case '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;is

12、lastNum = 1;break;case ' ':pStr+;break;default:pStr+;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",

13、(int)stackCali.Num);else if(stackCali.isOper = IS_OPER) printf("%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 = I

14、S_OPER)num1 = stackCalPop()->Num;num2 = stackCalPop()->Num; 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 : %fn", stackCal