How can I modify my Shunting-Yard Algorithm so it accepts unary operators?

Question

I\'ve been working on implementing the Shunting-Yard Algorithm in JavaScript for class.

Here is my work so far:

var userInput = prompt(\"Enter in a m         


        

Answer 1

To handle floating point numbers you can change your (number part of) regex to:

/([0-9]+\.?[0-9]*)/

so the final regex would be:

/([0-9]+\.?[0-9]*|[*+-\/()])/

And for handling unary minus operator, you can change it to another character like 'u'. (As it is explained here by -TGO)

The javascript code that i wrote for handling unary minus operator based on the link given is:

// expr is the given infix expression from which, all the white spaces has been
// removed.(trailing and leading and in between white space characters)
const operators = ['+', '*', '-', '/', '^'];
const openingBrackets = ['(', '[', '{'];
let exprArr = Array.from(expr);
// Since strings are immutable in js, I am converting it to an array for changing 
// unary minus to 'u'
for (let i = 0; i < expr.length; i++) {
    if (expr[i] === '-') {
        if (i === 0) {
            exprArr[i] = 'u';
        } else if (operators.includes(expr[i - 1])) {
            exprArr[i] = 'u';
        } else if (openingBrackets.includes(expr[i - 1])) {
            exprArr[i] = 'u';
        } else {
            // '-' is not a unary operator
            // it is a binary operator or we have the wrong expression, so...
            if (!openingBrackets.includes(expr[i + 1]) && !/[0-9]/.test(expr[i + 1])) {
                throw new Error("Invalid Expression...");
            }
        }
    }
}
// And finally converting back to a string.
let expr2 = exprArr.join('');