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Apr 16th, 2006, 2:36 AM
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#1 |
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function for precedence
Iam building a calculator in c++.I have implement a recursive function to do + - /
and *.But the calculator must be be based on level of precedence of operator.Can anyone know how to make a function to recognize precedence?? (the function must not using stack,or infix to postfix) but may be recursive or iterative?? Hope u can help |
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Apr 16th, 2006, 2:46 AM
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#2 |
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Multiplication and division have the same precedence as each other. Addition has the same precedence as subtraction, The precedence of multiplication is greater than that of addition. That's why (mathematically) 10-2*4 equates to 2 rather than 32 (which would be the result if subtraction had higher precedence than multiplication).
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Apr 16th, 2006, 8:05 AM
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#3 |
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Just to add on to grumpy. If you wanted to manipulate the order of operations, you could add parenthases. So..
10 - 2 * 4 = 8 but.. (10 - 2) * 4 = 32 Stuff inside the parenthases is evaluated before anything else. (there are a few exceptions in normal math) |
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Apr 17th, 2006, 12:06 AM
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#4 |
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I can suggest, since that would obviously be one line of input (10-2*4), to have an if>then statement that looks first for an * or / symbol, then evaluate that, then after that to look for a + or - symbol and evaluate for that.
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Apr 17th, 2006, 12:09 AM
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#5 |
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we used to have to take tests with huge equations/functions and have to break them down. Honestly, its easiest to use parentheses all the time. Even if you dont have to, its just reassuring to know you have to presenence right
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Apr 17th, 2006, 10:18 AM
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#6 | |
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Apr 17th, 2006, 1:12 PM
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#7 |
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Maybe you should take a look at converting from infix to postfix expressions.
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Apr 17th, 2006, 3:54 PM
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#8 | ||
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Abstraction doesn't make it impossible to write bad code; it makes it possible to write superior code. Contributor's Corner: Grumpy on C++ Exceptions DaWei on Pointers |
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Apr 17th, 2006, 4:36 PM
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#9 | |
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Apr 18th, 2006, 1:20 AM
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#10 |
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c'mon guys, everybody knows that 8 = 2, duh.
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i put on my robe and wizard hat... Have you ever heard of Plato, Aristotle, Socrates?...Morons. |
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