将变量从一种方法发送到另一种方法

Question

因此，我有一个程序可以计算平均成绩，最高成绩，最低成绩以及没有最低成绩的平均值。 因此，对于确定没有最低成绩的新平均值的方法，我想使用在该方法中已经找到的最低成绩。

/**
 * lowestGrade() - method will return lowest grade
 * @return lowGrade
 */
public static double lowestGrade(double[] grades) {

    double lowGrade = 100.0;

    // for loop that goes through grades array and stores
    // first grade found as highest grade
    for (int i = 0; i < grades.length; i++) {

        // if statement will determine true lowest grade
        if ( grades[i] < lowGrade ) {
            lowGrade = grades[i];
        }
    }

    // Output
    return lowGrade;
}

/**
 * averageWOLowGrade() - method will calculate average without lowest grade
 * @return newAverage
 */
public static void averageWOLowGrade(double[] grades) {
    double newAverage = 0;  
}

Answer 1

如前所述之前 ，你可以存储在字段中的最低等级：

private static double min = 0.0;

public static double lowestGrade(double[] grades) {
    // Set min and return its value.
    return min = DoubleStream.of(grades).min().getAsDouble();
}

public static double averageWOLowGrade(double[] grades) {
    return DoubleStream.of(grades).filter(x -> x != min)
                                  .average()
                                  .getAsDouble();
}

请记住，执行顺序在这里很重要。 我宁愿计算值两次，而不是在静态变量中管理状态。 甚至更好：一次计算所有结果：

public static Stats computeStats(double[] grades) {
    double min, max;
    min = max = grades[0];
    double sum = 0.0;

    for (double grade : grades) {
        if (grade < min) {
            min = grade;
        } else if (grade > max) {
            max = grade;
        }
        sum += grade;
    }

    double avg = sum / grades.length;
    int len = 0;
    sum = 0.0;

    for (double grade : grades) {
        if (grade != min) {
            sum += grade;
            len++;
        }
    }

    return new Stats(min, max, avg, sum / len);
}

static class Stats {
    public final double min;
    public final double max;
    public final double avg;
    public final double avgWithoutMin;

    Stats(double min, double max, double avg, double avgWithoutMin) {
        this.min = min;
        this.max = max;
        this.avg = avg;
        this.avgWithoutMin = avgWithoutMin;
    }
}