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java 程序,通过scanner 编写计算器
package test; import java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; class Calculator { private Double num1; private Double num2; private String var; private Scanner input; public Double getNum1() { return num1; } public void setNum1(Double num1) { this.num1 = num1; } public Double getNum2() { return num2; } public void setNum2(Double num2) { this.num2 = num2; } public String getVar() { return var; } public void setVar(String var) { this.var = var; } public Scanner getInput() { return input; } public void setInput(Scanner input) { this.input = input; } public boolean input1(){ System.out.println("请输入第一个数字"); String num1Str = input.next(); if(!this.isNumber(num1Str)){ input1(); }else{ this.num1 =Double.valueOf(num1Str); } return true; } public boolean input2(){ System.out.println("输入第二个数:"); String num2Str = input.next(); if(!this.isNumber(num2Str)){ input2(); }else if(var.equalsIgnoreCase("/")&&num2Str.equalsIgnoreCase("0")){ System.err.println("除数不能为0"); input2(); }else{ this.num2 =Double.valueOf(num2Str); } return true; } public boolean inputVar(){ System.out.println("输入计算符号:+ - * /"); String varStr=input.next(); Pattern pat=Pattern.compile("[+-\\\\*/]"); Matcher match=pat.matcher(varStr); boolean flag=match.matches(); if(flag==false){ System.err.println("运算符号不正确!"); inputVar(); }else{ this.setVar(varStr); } return true; } public void goCal(){ Scanner input= new Scanner(System.in); this.setInput(input); boolean flag1=this.input1(); if(flag1){ if(this.inputVar()){ if(this.input2()){ calculate(); } } } } public void calculate(){ try { switch (var) { case "+": System.out.println(num1+"+"+num2+"="+(num1+num2)); break; case "-": System.out.println(num1+"-"+num2+"="+(num1-num2)); break; case "*": System.out.println(num1+"-"+num2+"="+(num1*num2)); break; case "/": System.out.println(num1+"/"+num2+"="+(num1/(double)num2)); break; default: break; } } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); if(input!=null){ input.close(); System.exit(0); } } if(input!=null){ input.close(); System.exit(0); } } public boolean isNumber(Object obj){ if(obj==null||obj.toString().equals("")){ return false; } Pattern pattern=Pattern.compile("[0-9]+.*[0-9]*"); String str=obj.toString(); Matcher matcher=pattern.matcher(str); boolean flag=matcher.matches(); if(flag==false){ System.err.println("请输入有效数值!"); } return flag; } } public class TestB { public static void main(String[] args) { Calculator cal = new Calculator(); cal.goCal(); } }
java 程序,通过scanner 编写计算器
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