Round & FormatNumber 四捨五入的區別

VBScript Round() 四捨五入函數，但是使用 Round() 四捨五入為近偶取整，平時多數是以大於等於 5 的數值進位、小於 5 的數值捨去。FormatNumber() 的值比較符合平常用的值。使用 Round() 近偶取整則於偶數才進位與 FormatNumber() 四捨五入有差異由下表來分析差異點。這種方式可以減少四捨五入誤差的累積，但也可能造成一些不符合預期的結果，所產生的誤差。

運算的數值	Round()	FormatNumber()	差異處
0.1	Round(0.1, 0) = 0	FormatNumber(0.1, 0) = 0	-
0.2	Round(0.2, 0) = 0	FormatNumber(0.2, 0) = 0	-
0.3	Round(0.3, 0) = 0	FormatNumber(0.3, 0) = 0	-
0.4	Round(0.4, 0) = 0	FormatNumber(0.4, 0) = 0	-
0.5	Round(0.5, 0) = 0	FormatNumber(0.5, 0) = 1	差異處
0.6	Round(0.6, 0) = 1	FormatNumber(0.6, 0) = 1	-
0.7	Round(0.7, 0) = 1	FormatNumber(0.7, 0) = 1	-
0.8	Round(0.8, 0) = 1	FormatNumber(0.8, 0) = 1	-
0.9	Round(0.9, 0) = 1	FormatNumber(0.9, 0) = 1	-
1.0	Round(1.0, 0) = 1	FormatNumber(1.0, 0) = 1	-
1.1	Round(1.1, 0) = 1	FormatNumber(1.1, 0) = 1	-
1.2	Round(1.2, 0) = 1	FormatNumber(1.2, 0) = 1	-
1.3	Round(1.3, 0) = 1	FormatNumber(1.3, 0) = 1	-
1.4	Round(1.4, 0) = 1	FormatNumber(1.4, 0) = 1	-
1.5	Round(1.5, 0) = 2	FormatNumber(1.5, 0) = 2	-
1.6	Round(1.6, 0) = 2	FormatNumber(1.6, 0) = 2	-
1.7	Round(1.7, 0) = 2	FormatNumber(1.7, 0) = 2	-
1.8	Round(1.8, 0) = 2	FormatNumber(1.8, 0) = 2	-
1.9	Round(1.9, 0) = 2	FormatNumber(1.9, 0) = 2	-
2.0	Round(2.0, 0) = 2	FormatNumber(2.0, 0) = 2	-
2.1	Round(2.1, 0) = 2	FormatNumber(2.1, 0) = 2	-
2.2	Round(2.2, 0) = 2	FormatNumber(2.2, 0) = 2	-
2.3	Round(2.3, 0) = 2	FormatNumber(2.3, 0) = 2	-
2.4	Round(2.4, 0) = 2	FormatNumber(2.4, 0) = 2	-
2.5	Round(2.5, 0) = 2	FormatNumber(2.5, 0) = 3	差異處
2.6	Round(2.6, 0) = 3	FormatNumber(2.6, 0) = 3	-
2.7	Round(2.7, 0) = 3	FormatNumber(2.7, 0) = 3	-
2.8	Round(2.8, 0) = 3	FormatNumber(2.8, 0) = 3	-
2.9	Round(2.9, 0) = 3	FormatNumber(2.9, 0) = 3	-
3.0	Round(3.0, 0) = 3	FormatNumber(3.0, 0) = 3	-
3.1	Round(3.1, 0) = 3	FormatNumber(3.1, 0) = 3	-
3.2	Round(3.2, 0) = 3	FormatNumber(3.2, 0) = 3	-
3.3	Round(3.3, 0) = 3	FormatNumber(3.3, 0) = 3	-
3.4	Round(3.4, 0) = 3	FormatNumber(3.4, 0) = 3	-
3.5	Round(3.5, 0) = 4	FormatNumber(3.5, 0) = 4	-
3.6	Round(3.6, 0) = 4	FormatNumber(3.6, 0) = 4	-
3.7	Round(3.7, 0) = 4	FormatNumber(3.7, 0) = 4	-
3.8	Round(3.8, 0) = 4	FormatNumber(3.8, 0) = 4	-
3.9	Round(3.9, 0) = 4	FormatNumber(3.9, 0) = 4	-
4.0	Round(4.0, 0) = 4	FormatNumber(4.0, 0) = 4	-
4.1	Round(4.1, 0) = 4	FormatNumber(4.1, 0) = 4	-
4.2	Round(4.2, 0) = 4	FormatNumber(4.2, 0) = 4	-
4.3	Round(4.3, 0) = 4	FormatNumber(4.3, 0) = 4	-
4.4	Round(4.4, 0) = 4	FormatNumber(4.4, 0) = 4	-
4.5	Round(4.5, 0) = 4	FormatNumber(4.5, 0) = 5	差異處
4.6	Round(4.6, 0) = 5	FormatNumber(4.6, 0) = 5	-
4.7	Round(4.7, 0) = 5	FormatNumber(4.7, 0) = 5	-
4.8	Round(4.8, 0) = 5	FormatNumber(4.8, 0) = 5	-
4.9	Round(4.9, 0) = 5	FormatNumber(4.9, 0) = 5	-
5.0	Round(5.0, 0) = 5	FormatNumber(5.0, 0) = 5	-
5.1	Round(5.1, 0) = 5	FormatNumber(5.1, 0) = 5	-
5.2	Round(5.2, 0) = 5	FormatNumber(5.2, 0) = 5	-
5.3	Round(5.3, 0) = 5	FormatNumber(5.3, 0) = 5	-
5.4	Round(5.4, 0) = 5	FormatNumber(5.4, 0) = 5	-
5.5	Round(5.5, 0) = 6	FormatNumber(5.5, 0) = 6	-
5.6	Round(5.6, 0) = 6	FormatNumber(5.6, 0) = 6	-
5.7	Round(5.7, 0) = 6	FormatNumber(5.7, 0) = 6	-
5.8	Round(5.8, 0) = 6	FormatNumber(5.8, 0) = 6	-
5.9	Round(5.9, 0) = 6	FormatNumber(5.9, 0) = 6	-
6.0	Round(6.0, 0) = 6	FormatNumber(6.0, 0) = 6	-
6.1	Round(6.1, 0) = 6	FormatNumber(6.1, 0) = 6	-
6.2	Round(6.2, 0) = 6	FormatNumber(6.2, 0) = 6	-
6.3	Round(6.3, 0) = 6	FormatNumber(6.3, 0) = 6	-
6.4	Round(6.4, 0) = 6	FormatNumber(6.4, 0) = 6	-
6.5	Round(6.5, 0) = 6	FormatNumber(6.5, 0) = 7	差異處
6.6	Round(6.6, 0) = 7	FormatNumber(6.6, 0) = 7	-
6.7	Round(6.7, 0) = 7	FormatNumber(6.7, 0) = 7	-
6.8	Round(6.8, 0) = 7	FormatNumber(6.8, 0) = 7	-
6.9	Round(6.9, 0) = 7	FormatNumber(6.9, 0) = 7	-
7.0	Round(7.0, 0) = 7	FormatNumber(7.0, 0) = 7	-
7.1	Round(7.1, 0) = 7	FormatNumber(7.1, 0) = 7	-
7.2	Round(7.2, 0) = 7	FormatNumber(7.2, 0) = 7	-
7.3	Round(7.3, 0) = 7	FormatNumber(7.3, 0) = 7	-
7.4	Round(7.4, 0) = 7	FormatNumber(7.4, 0) = 7	-
7.5	Round(7.5, 0) = 8	FormatNumber(7.5, 0) = 8	-
7.6	Round(7.6, 0) = 8	FormatNumber(7.6, 0) = 8	-
7.7	Round(7.7, 0) = 8	FormatNumber(7.7, 0) = 8	-
7.8	Round(7.8, 0) = 8	FormatNumber(7.8, 0) = 8	-
7.9	Round(7.9, 0) = 8	FormatNumber(7.9, 0) = 8	-
8.0	Round(8.0, 0) = 8	FormatNumber(8.0, 0) = 8	-
8.1	Round(8.1, 0) = 8	FormatNumber(8.1, 0) = 8	-
8.2	Round(8.2, 0) = 8	FormatNumber(8.2, 0) = 8	-
8.3	Round(8.3, 0) = 8	FormatNumber(8.3, 0) = 8	-
8.4	Round(8.4, 0) = 8	FormatNumber(8.4, 0) = 8	-
8.5	Round(8.5, 0) = 8	FormatNumber(8.5, 0) = 9	差異處
8.6	Round(8.6, 0) = 9	FormatNumber(8.6, 0) = 9	-
8.7	Round(8.7, 0) = 9	FormatNumber(8.7, 0) = 9	-
8.8	Round(8.8, 0) = 9	FormatNumber(8.8, 0) = 9	-
8.9	Round(8.9, 0) = 9	FormatNumber(8.9, 0) = 9	-
9.0	Round(9.0, 0) = 9	FormatNumber(9.0, 0) = 9	-
9.1	Round(9.1, 0) = 9	FormatNumber(9.1, 0) = 9	-
9.2	Round(9.2, 0) = 9	FormatNumber(9.2, 0) = 9	-
9.3	Round(9.3, 0) = 9	FormatNumber(9.3, 0) = 9	-
9.4	Round(9.4, 0) = 9	FormatNumber(9.4, 0) = 9	-
9.5	Round(9.5, 0) = 10	FormatNumber(9.5, 0) = 10	-
9.6	Round(9.6, 0) = 10	FormatNumber(9.6, 0) = 10	-
9.7	Round(9.7, 0) = 10	FormatNumber(9.7, 0) = 10	-
9.8	Round(9.8, 0) = 10	FormatNumber(9.8, 0) = 10	-
9.9	Round(9.9, 0) = 10	FormatNumber(9.9, 0) = 10	-

Round() 及 FormatNumber() Rounding 主要差異處比較

FormatNumber() 函數

FormatNumber(2.5,0)

FormatNumber(4.5,0)

FormatNumber(6.5,0)

FormatNumber(8.5,0)

Round() 函數

Round(2.5)

Round(4.5)

Round(6.5)

Round(8.5)

Coding 時 ASP 四捨五入函數之使用則依照需求來選擇 Round() 及 FormatNumber() 函數。

ASPX IEEEremainder

Math.IEEEremainder(Double, Double) 傳回指定數字除以另一個指定數字所得的餘數，根據 IEEE 754 二進位浮點數算術標準。使用 Math.IEEEremainder 可以避免舍入誤差，並且保持與 IEEE 754 標準的一致性。例如在計算角度或周期性函數時，可以使用 Math.IEEEremainder 來將角度限制在一個範圍內，而不會出現負數或超過 360 度的情況。IEEE 754 標準是定義浮點數表示和運算的國際標準。浮點數是用來近似表示實數的數值格式，它由符號位、指數位和有效數位組成。IEEE 754 標準規定了不同的浮點數格式，例如單精度、雙精度和擴展精度，以及相關的運算規則，常使用於加法、減法、乘法、除法和取餘數。IEEE 754 標準還定義特殊的浮點數值，例如無窮大、非數和捨入模式。IEEE 754 標準的目的是為了提供一種可移植和可靠的浮點數計算方法，並且能夠處理各種異常情況。