java加减乘除运算的程序怎么编？

//JAVA编程:四则运算(接收用户输入的2个 *** 作数，和运算符)，计算之后，输出结果~~~~\x0d\x0aimportjava.util.Scanner\x0d\x0apublicclass四则运算{\x0d\x0apublicstaticvoidmain(String[]args){\x0d\x0aScannersc=newScanner(System.in)\x0d\x0aSystem.out.print("请输入第一个数字：")\x0d\x0ainta=sc.nextInt()\x0d\x0aSystem.out.print("请输入运算符号：")\x0d\x0aStringstr=sc.next()\x0d\x0acharch=str.charAt(0)\x0d\x0aSystem.out.print("请输入第二个数字：")\x0d\x0aintb=sc.nextInt()\x0d\x0aswitch(ch)\x0d\x0a{\x0d\x0acase'+':\x0d\x0aSystem.out.println(a+"+"+b+"="+(a+b))\x0d\x0abreak\x0d\x0acase'-':\x0d\x0aSystem.out.println(a+"-"+b+"="+(a-b))\x0d\x0abreak\x0d\x0acase'*':\x0d\x0aSystem.out.println(a+"*"+b+"="+(a*b))\x0d\x0abreak\x0d\x0acase'/':\x0d\x0aif(b==0){\x0d\x0aSystem.out.println("被除数为零，运算无意义!")\x0d\x0abreak\x0d\x0a}\x0d\x0aelse{\x0d\x0aSystem.out.println(a+"/"+b+"="+(a/b))\x0d\x0abreak\x0d\x0a}\x0d\x0adefault:\x0d\x0aSystem.out.println("运算符是无意义字符！")\x0d\x0abreak\x0d\x0a}\x0d\x0a}\x0d\x0a}\x0d\x0a\x0d\x0a望采纳~~~~~~~~

import java.util.Scanner

public class HybridOperation {

public static void main(String[] args) {

Scanner input = new Scanner(System.in)

System.out.println("输入一个表达式:")

String s = input.nextLine().trim()

int n = s.length()

int sum = 0

int p = -1

char a = '+'

for (int i = 1i <ni++) {

char ch = s.charAt(i)

if (ch == '+' || ch == '-') {

if (a == '+') {

sum += Integer.parseInt(s.substring(p + 1, i))

a = ch

p = i

} else if (a == '-') {

sum -= Integer.parseInt(s.substring(p + 1, i))

a = ch

p = i

}

}

}

if (a == '+') {

sum += Integer.parseInt(s.substring(p + 1))

}

if (a == '-') {

sum -= Integer.parseInt(s.substring(p + 1))

}

System.out.println(s+" = "+sum)

}

}

可以实现任意次数的加减，

如：1+2+3-2

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