Re: [其他] 0.1+0.1+0.1-0.3=?已回收
※ 引述《WC (World Cup)》之銘言:
: 那不知道可不可以請程式語言老師不常請假的 gomi 簡單的說明為什麼
: 只有 0.1+0.1+0.1-0.3 會這樣
: 0.1+0.1-0.2 就是等於 0
: 0.1+0.1+0.1+0.1-0.4 也是等於零
: 連 (1/3+1/3+1/3)-1 都等於零了, 為什麼只有這個例子是這樣
: 謝謝
噓文的空間不夠長,只好用回的了....
0.1= 0 01111111011 1001100110011001100110011001100110011001100110011010
xxx
0.2= 0 01111111100 1001100110011001100110011001100110011001100110011010
兩個 mantissa "完全一樣" =>0.1 + 0.1 "=" 0.2, 只有exponent不同
0.1+0.1+0.1=0 2^-4 1.1001100110011001100110011001100110011001100110011010
+)0 2^-4 1.1001100110011001100110011001100110011001100110011010
+)0 2^-4 1.1001100110011001100110011001100110011001100110011010
0 2^-4 100.1100110011001100110011001100110011001100110011001110
>>
= 0 2^-2 1.00110011001100110011001100110011001100110011001100111
rounding
= 0 01111111101 0011001100110011001100110011001100110011001100110100
XXX
0.3= 0 01111111101 0011001100110011001100110011001100110011001100110011
that's the difference
我竟然在做電腦才該有耐心做完的事.....
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你想做真正的分數運算,去找CAS... matlab不是這樣用的
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※ 編輯: kdjf 來自: 140.112.245.32 (06/24 10:55)
※ 編輯: kdjf 來自: 140.112.245.32 (06/24 10:55)
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