Java 汇总

Question

我怎样才能将 numberGrade 的值调高，如果它是 89.5，它会变成 90。numberGrade 被当作 double ，但将它设为 int 并不会向上或向下舍入。

public class GradeReporter
{
    // The limit is the inclusive lower limit for each letter
    // grade -- this means that 89.5 is an 'A' not a 'B'
    public static final double A_LIMIT = 90;
    public static final double B_LIMIT = 80;
    public static final double C_LIMIT = 70;
    public static final double D_LIMIT = 60;
    public static final double F_LIMIT = 60;

    /** Converts a numeric grade into a letter grade. Grades should be rounded to 
     *  nearest whole number
     *
     * @param a numeric grade in the range of 0 to 100
     * @returns a letter grade based on the numeric grade, possible grades are A, B, C, D and F.
     */
    public char letterGrade(double numberGrade)
    {
        int grade = int(numberGrade);
        if (grade >= A_LIMIT)
            letterGrade = 'A';
        else if (grade >= B_LIMIT)
            letterGrade = 'B';
        else if (grade >= C_LIMIT)
            letterGrade = 'C';
        else if (grade >= D_LIMIT)
            letterGrade = 'D';
        else if (grade < F_LIMIT)//4
            letterGrade = 'F';
        return letterGrade;
    }

Answer 1

要向上舍入，您可以使用Math.ceil(numberGrade)。要舍入到最接近的整数，请使用 Math.round(numberGrade)。

参见:the Math class