java - 如何除以得到十进制值？

Question

我想知道如何在 Java 中获取单个值的余数和商。

例子：

3/2 我应该得到 1.5 的值。

如果我使用/运算符，我只会得到商。如果我使用%操作员，我只会得到剩余部分。如何在同一个变量中同时获得两者？

Answer 1

quotient = 3 / 2;
remainder = 3 % 2;

// now you have them both

Answer 2

在您的示例中，Java 正在执行整数运算，四舍五入除法的结果。

根据您的问题，您想执行浮点运算。为此，您的术语中的至少一项必须指定为（或转换为）浮点数：

指定浮点数：

3.0/2
3.0/2.0
3/2.0

转换为浮点数：

int a = 2;
int b = 3;
float q = ((float)a)/b;

或者

double q = ((double)a)/b;

（有关 和 的讨论，请参阅Java陷阱：double和Java Floating-Point Number Intricacies）floatdouble

Answer 3

看看这个：http: //download.oracle.com/javase/1,5.0/docs/api/java/math/BigDecimal.html#divideAndRemainder%28java.math.BigDecimal%29

您只需将int或long变量包装在BigDecimal对象中，然后对其调用divideAndRemainder方法。返回的数组将包含商和余数（按该顺序）。

Answer 4

Don't worry about it. In your code, just do the separate / and % operations as you mention, even though it might seem like it's inefficient. Let the JIT compiler worry about combining these operations to get both quotient and remainder in a single machine instruction (as far as I recall, it generally does).

Answer 5

如果你将两个参数都初始化为float，你肯定会得到实际的分值。例如：

float RoomWidth, TileWidth, NumTiles;
RoomWidth = 142;
TileWidth = 8;
NumTiles = RoomWidth/TileWidth;

答：17.75。

Answer 6

你可以这样做，

int a = 3;
int b = 2;
int quotient = a / b;
int remainder = a % b;

得到实数的商

System.out.println((double) a / b);

获得整数的商

System.out.println("Quotient: " + quotient);
System.out.println("Remainder: " + remainder);

得到实数的商，使得小数点后有一个数字

System.out.println(a / b + "." + a % b * 10 / b);

注意：在最后一种方法中，它不会将小数点后的数字四舍五入。

Answer 7

我的意思是这很简单。将其设置为双精度。所以让我们说

double answer = 3.0/2.0;
System.out.print(answer);

Answer 8

int a = 3;
int b = 2;
float c = ((float)a)/b

Answer 9

请将您的输入转换为双倍并除以。

Answer 10

@recursive 的解决方案（接受的答案）是 100% 正确的。我只是添加一个示例代码供您参考。

我的情况是用两位小数显示价格。这是后端响应的一部分："price": 2300, "currencySymbol": "CD", ...。

这是我的助手类：

public class CurrencyUtils
{
    private static final String[] suffix = { "", "K", "M" };

    public static String getCompactStringForDisplay(final int amount)
    {
        int suffixIndex;
        if (amount >= 1_000_000) {
            suffixIndex = 2;
        } else if (amount >= 1_000) {
            suffixIndex = 1;
        } else {
            suffixIndex = 0;
        }

        int quotient;
        int remainder;
        if (amount >= 1_000_000) {
            quotient = amount / 1_000_000;
            remainder = amount % 1_000_000;
        } else if (amount >= 1_000) {
            quotient = amount / 1_000;
            remainder = amount % 1_000;
        } else {
            return String.valueOf(amount);
        }

        if (remainder == 0) {
            return String.valueOf(quotient) + suffix[suffixIndex];
        }

        // Keep two most significant digits
        if (remainder >= 10_000) {
            remainder /= 10_000;
        } else if (remainder >= 1_000) {
            remainder /= 1_000;
        } else if (remainder >= 100) {
            remainder /= 10;
        }

        return String.valueOf(quotient) + '.' + String.valueOf(remainder) + suffix[suffixIndex];
    }
}

这是我的测试类（基于 Junit 4）：

public class CurrencyUtilsTest {

    @Test
    public void getCompactStringForDisplay() throws Exception {
        int[] numbers = {0, 5, 999, 1_000, 5_821, 10_500, 101_800, 2_000_000, 7_800_000, 92_150_000, 123_200_000, 9_999_999};
        String[] expected = {"0", "5", "999", "1K", "5.82K", "10.50K", "101.80K", "2M", "7.80M", "92.15M", "123.20M", "9.99M"};

        for (int i = 0; i < numbers.length; i++) {
            int n = numbers[i];
            String formatted = CurrencyUtils.getCompactStringForDisplay(n);
            System.out.println(n + " => " + formatted);

            assertEquals(expected[i], formatted);
        }
    }

}