java - 与选择混淆( float )

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我正在在线学习 Java，但遇到了问题。我知道它可能与 BigDecimal 类有关，但除此之外我不确定。抱歉缩进不好。

public class Practice {
     
    public static void main(String[] args) {
         
        double b = 1.3333;
          
        int c = 4, d = 3;
          
        final double TOLERANCE = 0.001;

        /*** TODO: Write an if statement to serve as the header for the conditional block below.
                   Execute the first block if the floating point outcome of c divided by d is 
                   within the given TOLERANCE of b. ***/
        
        {
            System.out.println("Value within the tolerance level!");
        } else {
            System.out.println("Value outside the tolerance level!");
        }
    }
}

Answer 1

/*** TODO: Write an if statement to serve as the header for the conditional block below.
     Execute the first block if the floating point outcome of c divided by d is 
     within the given TOLERANCE of b. ***/

您需要使用需要与容差进行比较的除法运算来完成缺失的 if 语句。除法运算应输出浮点数，并应与变量 b 进行比较检查它是否在公差范围内。
如果将两个整数相除，则称为整数除法，它再次产生整数。要获得浮点数，您需要将至少一个数字转换为浮点数。这是区别以及如何进行类型转换:

System.out.println(c / d); // result is 1, out of tolerance. this is integer division
System.out.println((float) c / d); // result is 1.3333334, within tolerance

与容差比较的另一点是，我们需要绝对差异进行比较。要做到这一点，有方法 abs()在 Math类(class): Math.abs(((float) c / d) - b)所以你的代码最后应该是这样的:

public static void main(String[] args) {
    double b = 1.3333;

    int c = 4, d = 3;

    final double TOLERANCE = 0.001;

    if (Math.abs(((float) c / d) - b) < TOLERANCE){
        System.out.println("Value within the tolerance level!");
    } else {
        System.out.println("Value outside the tolerance level!");
    }
}