java - 我的表输出的百分比值不正确

Question

public class apples {

private static String[] level1 = new String[] { "A", "B", "I", "K", "N", "O", "P", "S", "T", "W" };



public static void main(String[] args) {

        int[] scores1 = { 99, 80, 56, 88, 70, 35, 67, 60, 78, 56 };

        int[] correct1 = {20, 20, 13, 15, 22, 18, 19, 21, 23, 25};

        int[] incorrect1 = {2, 1, 5, 2, 2, 5, 8, 1, 0, 0};


        double[] percentage1 = new double[correct1.length];
        for(int a = 0; a < correct1.length; a++ ){ 
                 percentage1[a] = (double)((correct1[a] / (correct1[a] + incorrect1[a]))*100);
            }


        System.out.println("Character \t Correct \t Incorrect \t Percentage");
            for(int counter = 0; counter<scores1.length;counter++){
                System.out.println(level1[counter] + "\t\t " + correct1[counter] + "\t\t " + incorrect1[counter] + "\t\t " + percentage1[counter]);
            }


}

}

这将输出一个包含 4 个标题的表格。字符、正确和错误列按预期显示。但是百分比行无法正常工作。例如，字符“A”、正确 20 和错误 2 给出的百分比为 0.0。任何“不正确”值 > 0 都会输出百分比值 0，任何 = 0 的“不正确”值都会输出百分比值 100(这是正确的)...有人可以解释一下我哪里出了问题吗？

Answer 1

这里处理的是整数，对于整数除法，结果会被截断。您需要将原始值转换为 double，或者将一部分乘以 1.0 以获得 double 值:

percentage1[a] = ((correct1[a]*1.0 / (correct1[a] + incorrect1[a]))*100);