找到後綴以前綴表達式

Question

可能重複：
Postfix to Infix conversation

什麼是這個表達式的前綴符號？我無法解決這個表達式

6 a b 7 * + - c d g/+ e^f * + 

任何建議將不勝感激。

Answer 1

後綴爲綴::

6 a b 7 * + - c d g/+ e^f * + 

6 a (b*7) + - c d g/+ e^f * + 
6 {a + (b*7)} - c d g/+ e^f * + 
[6 - {a + (b*7)}] c d g/+ e^f * + 
[6 - {a + (b*7)}] c (d/g) + e^f * + 
[6 - {a + (b*7)}] {c + (d/g)} e^f * + 
[6 - {a + (b*7)}] [{c + (d/g)}^e] f * + 
[6 - {a + (b*7)}] ([{c + (d/g)}^e] * f) + 
[6 - {a + (b*7)}] + ([{c + (d/g)}^e] * f) 

綴前綴::

[6 - {a + (b*7)}] + ([{c + (d/g)}^e] * f) 

[6 - {a + (b*7)}] + *[{c + (d/g)}^e] f 
[6 - {a + (b*7)}] + *[{c + (/ d g)}^e] f 
[6 - {a + (b*7)}] + *[{+ c/d g}^e] f 
[6 - {a + (b*7)}] + (*^+ c/d g e f) 
[6 - {a + (*b7)}] + (*^+ c/d g e f) 
[6 - {+a *b7}] + (*^+ c/d g e f) 
[-6 +a *b7] + (*^+ c/d g e f) 
+[-6 +a *b7] (*^+ c/d g e f) 
+-6 +a *b7 *^+ c/d g e f 

Answer 2

的有序表達將是

[6-(a + b*7)] + [(c + d/g)^e]*f 

從您可以發現預順序，這是 + -6 + A * B 7 *^+ C/DGEF