java用逆波兰表达式实现字符串计算器

1、java版本

import java.math.BigDecimal;
import java.util.*;/*** @return* @author Tmz* @description:* 后缀表达式(逆波兰)规则：*  ①当前符号大于等于优先级大于等于栈顶优先级时弹出符号，并入栈当前符号 ，出栈的符号加入表达式末尾*  ②“(” 符号优先级最低*  ③ ")" 符号入栈是，符号出栈直到当前为 "(" ,并且该符号也要出栈，出栈的符号加入表达式末尾* 计算规则：*  遇到数字直接入栈，遇到操作符，则弹出两个项进行运算，将运算结果再入栈，最后栈底元素值则为最终结果* @date 2022/6/7 10:11*/public  class  HelloWorld {public static String[] operator = {"+", "-", "*", "/","%","^","(", ")"};public static void main(String[] args) {String expression = "-100**2";expression=expression.replaceAll("\\s+", ""); //去掉空格expression=expression.replace("**", "^"); //支持立方**这种写法expression=expression.replace("(-", "(0-"); //解决负数System.out.println(expression);
//        System.out.println(getExpressionStack(expression));polishNotation(expression);}public static void polishNotation(String expression) {List<String> expressionList = getExpressionStack(expression); //中值表达式栈List<String> expressionList2 = new ArrayList<>();if ("-".equals(expressionList.get(0))) { //处理开头是负数的情况，直接加上括号expressionList2.add("(");expressionList2.add("0");expressionList2.add(expressionList.get(0));expressionList2.add(expressionList.get(1));expressionList2.add(")");expressionList2.addAll(expressionList.subList(2,expressionList.size()));}Stack<String> operatorStack = new Stack<>(); //操作符栈ArrayList<String> fixStack = new ArrayList<>(); //完整的逆波兰表达式Map<String, Integer> operatorLevelMap = new HashMap<>();operatorLevelMap.put("(", 0);operatorLevelMap.put("+", 1);operatorLevelMap.put("-", 1);operatorLevelMap.put("*", 2);operatorLevelMap.put("/", 2);operatorLevelMap.put("%", 2);operatorLevelMap.put("^", 3);operatorLevelMap.put(")", 4);System.out.println(expressionList2);String[] operator2 = {"+", "-", "*", "/","%","^"};for (String currentElmt : expressionList2) {if (Arrays.asList(operator2).contains(currentElmt)) {while (!operatorStack.empty() && operatorLevelMap.get(operatorStack.peek()) >= operatorLevelMap.get(currentElmt)) {fixStack.add(operatorStack.pop());}operatorStack.push(currentElmt);}else if("(".equals(currentElmt)){operatorStack.push(currentElmt);} else if(")".equals(currentElmt)){while (!operatorStack.empty() && operatorLevelMap.get(operatorStack.peek()) >= operatorLevelMap.get("(")+1) {fixStack.add(operatorStack.pop());}if (!operatorStack.empty()) {operatorStack.pop();}}else{fixStack.add(currentElmt);}}while (!operatorStack.isEmpty()) {fixStack.add(operatorStack.pop());}System.out.println(fixStack);//计算结果Stack<String> calculateStack = new Stack<>();for (String fix : fixStack) {//操作符号,弹出两个数字计算，并压入结果栈中if (Arrays.asList(operator2).contains(fix)) {String number2 = calculateStack.pop();String number1 = calculateStack.pop();switch (fix) {case "+":calculateStack.push(new BigDecimal(number1).add(new BigDecimal(number2)).toString());break;case "-":calculateStack.push(new BigDecimal(number1).subtract(new BigDecimal(number2)).toString());break;case "*":calculateStack.push(new BigDecimal(number1).multiply(new BigDecimal(number2)).toString());break;case "/":calculateStack.push(String.valueOf(Double.valueOf(number1)/Double.valueOf(number2)));break;case "%":calculateStack.push(String.valueOf(Double.valueOf(number1)%Double.valueOf(number2)));break;case "^":calculateStack.push(String.valueOf(Math.pow(Double.valueOf(number1), Double.valueOf(number2))));break;}}else{//数字入栈calculateStack.push(fix);}}System.out.println(calculateStack.pop());}//把表达式转换为 栈public static List<String> getExpressionStack(String expression) {List<String> retList = new ArrayList<>();String fix = "";for (int i = 0; i < expression.length(); i++) {String tempStr = String.valueOf(expression.charAt(i));if (Arrays.asList(operator).contains(tempStr)) {if (!"".equals(fix)) {retList.add(fix);}retList.add(tempStr);fix = "";}else{fix = fix + tempStr;}}if(!"".equals(fix))retList.add(fix);return retList;}}

2、ahk版本

str:="-2**10"
;msgBox % 1 "+" 2
;msgBox % mod(3,2)
polish_notation(str)
return;逆波兰表达式https://blog.csdn.net/assiduous_me/article/details/101981332：
polish_notation(expression)
{operatorlevel_map:={"(":0,"+":"1","-":1,"*":2,"/":"2","%":2,"^":3,")":4}operator_list:={"+":0,"-":0,"*":0,"/":0,"%":0,"^":0};去除不必要的空格expression:=trim(expression)expression:=RegExReplace(expression,"\s+","");替换立方根StringReplace expression,expression,**,^,all;替换负数StringReplace expression,expression,`(-,`(0-,allmsgBox % expression;msgBox % expression;①.获取一个中缀表达式集合类似 100+2 -> ["100","+","2"]middlefix_list:=[]fix:=""loop ,parse,expression{current_value:=A_LoopFieldif(operatorlevel_map.haskey(current_value)){if(""!=fix)middlefix_list.push(fix)middlefix_list.push(current_value)fix:=""}else fix:=fix current_value}if(fix!="")middlefix_list.push(fix)if(middlefix_list[1]="-") ;处理开头为负数{middlefix_list.insertAt(1,"(")middlefix_list.insertAt(2,"0")middlefix_list.insertAt(5,")")};②.转换为后缀表达式(逆波兰表达式)operator_stack:=[]suffix_list:=[]for  index ,currentElmt in middlefix_list{if(operator_list.haskey(currentElmt)){while(operator_stack.length()>0 && operatorlevel_map[operator_stack[operator_stack.Length()]]>=operatorlevel_map[currentElmt])suffix_list.push(operator_stack.pop())operator_stack.push(currentElmt)}else if(currentElmt="(")operator_stack.push("(")else if(currentElmt=")"){while(operator_stack.length()>0 && operatorlevel_map[operator_stack[operator_stack.length()]]>operatorlevel_map["("])suffix_list.push(operator_stack.pop())if(operator_stack.length()>0)operator_stack.pop()}elsesuffix_list.push(currentElmt)}while(operator_stack.length()>0)suffix_list.push(operator_stack.pop());③.计算表达式最终的值，规则数字入栈，操作符就出栈两个元素计算值并把结果入栈number_stack:=[]for key,opertor_or_number in suffix_list{if(operator_list.haskey(opertor_or_number)){number2:=number_stack.pop()number1:=number_stack.pop()if(opertor_or_number="+")number_stack.push(number1+number2)if(opertor_or_number="-")number_stack.push(number1-number2)if(opertor_or_number="*")number_stack.push(number1*number2)if(opertor_or_number="/")number_stack.push(number1/number2)if(opertor_or_number="%")number_stack.push(mod(number1,number2))if(opertor_or_number="^")number_stack.push(number1**number2)}elsenumber_stack.push(opertor_or_number)}result:=number_stack.pop()msgBox % result}

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java用逆波兰表达式实现字符串计算器

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