除了整数以外，还要支持真分数的四则运算，真分数的运算，例如：/ + / = /

 运算符为 +, −, ×, ÷

 并且要求能处理用户的输入，并判断对错，打分统计正确率。

 要求能处理用户输入的真分数， 如 /, / 等

 使用 -n 参数控制生成题目的个数，例如执行下面命令将生成10个题目

 Myapp.exe -n 

public static int commonDivisor(int x, int y) // 计算2个数的最大公约数。按绝对值计算。

        {

            if (x == 0 || y == 0) {

                return 1;

            }

            int x1;

            int y1;

            x1 = (Math.abs(x) > Math.abs(y)) ? Math.abs(x) : Math.abs(y); // 使x1>y1.

            y1 = (Math.abs(x) > Math.abs(y)) ? Math.abs(y) : Math.abs(x);

            int z = 1;

            while (z != 0) {

                z = x1 % y1;

                x1 = y1;

                y1 = z;

            }

            return x1;

        }

    Calculator add(Calculator r) { // 加法运算

        int a = r.getNumerator();

        int b = r.getDenominator();

        int newNumerator = numerator * b + denominator * a;

        int newDenominator = denominator * b;

        int maxCommon = commonDivisor(newNumerator, newDenominator);

        Calculator result = new Calculator(newNumerator/ maxCommon, newDenominator/ maxCommon);

        return result;

    }

    Calculator sub(Calculator r) { // 减法运算

        int a = r.getNumerator();

        int b = r.getDenominator();

        int newNumerator = numerator * b - denominator * a;

        int newDenominator = denominator * b;

        int maxCommon = commonDivisor(newNumerator, newDenominator);

        Calculator result = new Calculator(newNumerator/ maxCommon, newDenominator/ maxCommon);

        return result;

    }

    Calculator muti(Calculator r) { // 乘法运算

        int a = r.getNumerator();

        int b = r.getDenominator();

        int newNumerator = numerator * a;

        int newDenominator = denominator * b;

        int maxCommon = commonDivisor(newNumerator, newDenominator);

        Calculator result = new Calculator(newNumerator/ maxCommon, newDenominator/ maxCommon);

        return result;

    }

    Calculator div(Calculator r) { // 除法运算

        int a = r.getNumerator();

        int b = r.getDenominator();

        int newNumerator = numerator * b;

        int newDenominator = denominator * a;

        int maxCommon = commonDivisor(newNumerator, newDenominator);

        Calculator result = new Calculator(newNumerator/ maxCommon, newDenominator/ maxCommon);

        return result;

    }