Find degree of equation in a string? [closed]

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In JAVA:-

Given an equation in a string: String equation = "4*x^3-19*x^2+2*x-1=0";, how to find its degree?

I thought of looping through the string finding positions of carets'^', get the numbers after the carets and the highest among them would be the degree of the equation. But what if the numbers are more than a single digit? Implementing this would be designing a parser of equations!

So can you tell me any other way?

Edit:

I'd like to know the way it can be done, for example using regular expressions as stated in one of the comments and not the code.

Answer 1

You can try something like this:

int degree = 1;
Matcher m = Pattern.compile("(?<=\\^)\\d+").matcher(equation);

while (m.find()) {
    int exp = Integer.parseInt(m.group());

    if (exp > degree)
        degree = exp;
}

We're finding all matches of (?<=\^)\d+. \d+ matches a string of 1 or more digits, and (?<=\^) is a positive lookbehind to ensure that these digits are preceded by a caret (but does not include this caret in the match).

Answer 2

You could use the following Regular Expression to match the values that are contained after a caret :

\^\d+

Which would explicitly match each value and then you could simply find the largest value that was matched and return it.

(Tutorial on Regular Expressions in Java)