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our homework is actually a long one, about numerical analysis, roots of poylnomials, etc. the problem is i don't know how to do the first step, which is storing/saving a user-input polynomial(eg this form: x^3-4x^2+2). do i use arrays?strings? and how do you save the polynomial as a function so that you can get the value of the polynomial when a value for x is given(say x = 2, then, from the ex above, f(x) = -6).
I don't know what option is best for your case, but why don't you experiment with different approaches?
say i use strings to store the polynomial, how can i save it as a function?
You can't save it directly as a function but rather pass it to a function that will translate it to the proper operations.
how?
I have an idea about how to store the polynomial. My opinion is, store it in a struct that has two elements: an integer "maxPow" that represents the bigger power and an array of size "maxPow" that will store the coefficients of each part of the polynomial.
For that you'll need to know how to parse math expressions. There are many tutorials online, compiler expression parsing such get you started! :)Quote:
Originally Posted by firehydrant
we haven't tackled structs yet in class, so as of the moment, i can't use those.
if i use strings to store the polynomial, is there a way to pick out the numeric parts of it? that way, i can assign it as coefficients or exponents in my function.
Of course there is, but as i said, that can be done by parsing the math expressions inside it.Quote:
Originally Posted by firehydrant
And since you don't know structs yet, this "translation" has to be done everytime you want to call that polynomial.
how do i do it exactly?
Search for Math Expression ParsingQuote:
Originally Posted by firehydrant
ok
Thanks!
The simplest way is ask user from number of degree(n).
and ask coefficient of each term.
Code:Deg of polynomial: 2
coefficient of x^2 : 1
coefficient of x^1 : -4
coeficient of x^0 : 2
i have a suggestion. but i think it will make the program a bit lengthy.
anyway let me.
i think u ppl hav heard about infix and postfix expressions.
first of all, consider the input polynomial as an INFIX expression.
convert it to POSTFIX and then evaluate it by giving values to variables.
how do you that math expression parsing?
I wonder if parsing an arbitrary function is beyond what's expected for your assignment.
Perhaps the user can input the coefficients in another way - using multiple input prompts.
For example, "Enter coefficient for C"... "X"... "X^2"... "X^3"... These would all go into a simple array. The to evaluate you simply loop through that.
I already did a version just like what you said for my program, as a last resort. But it's required that the user will input the whole polynomial. Right now, I'm trying to do a polynomial parser, and it doesn't work T_T