java - 解析问题和数字 "doing math"(一个简单的 java 计算器)

Question

我正在尝试获取一个简单的 String 语句并解析它以打印出一个简单的答案。

到目前为止，我不明白为什么我总是得到错误的答案。

举例来说 - 我插入一个带有“2 * 3 * 4 * 5/2/3/2”的字符串。

预期答案是 10，但我收到的答案是 1.5

有人能看到这里的问题吗？我认为这不是操作顺序的情况(我还没有做到这一点)。

public class TestingforExcel {
    static String tableholder = "2 * 3 * 4 * 5 / 2 / 3 / 2";
    public static void main(String args[]){
        String[] fracEquationHolder = tableholder.split(" ",tableholder.length()); // holds the fractions and operator
        String operators = "";
        double operand;
        double operand2;
        double answer = 0;

        for(int i =0; i <= (fracEquationHolder.length-2); i+=2){
            operators = fracEquationHolder[i+1];
            operand = Double.parseDouble(fracEquationHolder[i]);
            operand2 = Double.parseDouble(fracEquationHolder[i+2]);
            if(operators.indexOf("+")>=0){
                answer = operand + operand2;
            }else if(operators.indexOf("-")>=0){
                answer = operand - operand2;
            }else if(operators.indexOf("*")>=0){
                answer = operand * operand2;
            }else if(operators.indexOf("/")>=0){
                answer = operand / operand2;
            }else
                System.out.print(answer+""); 
        }
        System.out.print(answer+""); 

    }

Answer 1

public class TestingforExcel {
    static String tableholder = "2 * 3 * 4 * 5 / 2 / 3 / 2";
    public static void main(String args[]){
         String[] fracEquationHolder = tableholder.split(" ",tableholder.length()); // holds the fractions and operator
        String operators = "";
        double operand;
        double operand2;
        double answer = Double.parseDouble(fracEquationHolder[0]);

        for(int i =0; i <= (fracEquationHolder.length-2); i+=2){
            operators = fracEquationHolder[i+1];
            operand = Double.parseDouble(fracEquationHolder[i]);
            operand2 = Double.parseDouble(fracEquationHolder[i+2]);
            if(operators.indexOf("+")>=0){
                answer += operand2;
            }else if(operators.indexOf("-")>=0){
                answer -= operand2;
            }else if(operators.indexOf("*")>=0){
                answer *=  operand2;
            }else if(operators.indexOf("/")>=0){
                answer /=   operand2;
            }else
                System.out.print(answer+""); 
        }
        System.out.print(answer+""); 

    }

你必须面对的问题:

1- 您得到 1.5，因为这是最后一次操作 (3/2) 您应该使用(答案+=操作数+操作数2)

2-您应该使用最后一次操作的总和而不是操作数