java - 我输入了正确的值但打印了错误的值

Question

我输入了正确的值，但打印出错误的值。 (*商数显示到小数点后第一位。)

System.out.printf ("What is quotient of %d / %d ? ", n1, n2);
double answer1 = s.nextDouble();  //enter quotient

System.out.printf("What is remainder of %d / %d ? ", n1, n2);
double answer2 = s.nextDouble();  //enter remainder

if ((quotient == answer1) && (((n1-(quotient*n2)) == answer2)))
  System.out.print("Correct!");

else {  System.out.print("Incorrect: ");  //error point I think
System.out.printf("%d / %d = %f, Remainder: %f \n", n1, n2, quotient, (n1-(quotient*n2)));   }

当问题是 6/7 时，如果我输入正确答案 0.8，其余答案为 0.4，则显示“不正确:6/7 = 0.800000，余数:0.400000”而不是“正确!”我该怎么办？

Answer 1

这是由于浮点运算和精度。差异可能在逗号后的第 10 位。因此，您不应将 float 与 == 进行比较，而应检查它们的差异是否低于某个阈值。

double a = ...;
double b = ...;

if (Math.abs(a-b) < 0.0001) {
  //Consider as equal
} else { 
  //Consider as unequal
}