RPN calculator (Swift xcode) - sine, cosine, tangent, reciprocal (1/x), log (base) functions

Question

I have build a basic RPN calculator with Swift and I need to add those functions: sine, cosine, tangent, reciprocal (1/x), log (base) & log (base10). Here is the code that I have for the basic operations:

import Foundation
import UIKit

class CalculatorEngine: NSObject
{
    var operandStack = Array<Double>() //array

    func updateStackWithValue(value: Double)
    { self.operandStack.append(value) }

    func operate(operation: String) ->Double
    { switch operation

    {

    case "×":
        if operandStack.count >= 2 {
            return self.operandStack.removeLast() * self.operandStack.removeLast()
        }


    case "÷":
        if operandStack.count >= 2 {
            return self.operandStack.removeFirst() / self.operandStack.removeLast()
        }


    case "+":
        if operandStack.count >= 2 {
            return self.operandStack.removeLast() + self.operandStack.removeLast()
        }

    case "−":
        if operandStack.count >= 2 {
            return self.operandStack.removeFirst() - self.operandStack.removeLast()
        }

    case "√":
        if operandStack.count >= 1 {
            return sqrt(self.operandStack.removeLast())
        }

    default:break
        }
        return 0.0
    }

Answer 1

Here is an implementation of those basic functions in Swift. I'll let you put that into your RPN calculator, since that is your assignment.

The built-in trig functions need input in radians, so you have to convert by multiplying by pi and dividing by 180.0.

func sine(degrees: Double) -> Double {
    return sin(degrees * M_PI / 180)
}

func cosine(degrees: Double) -> Double {
    return cos(degrees * M_PI / 180)
}

func tangent(degrees: Double) -> Double {
    return tan(degrees * M_PI / 180)
}

func log(n: Double, base: Double) -> Double {
    return log(n) / log(base)
}

func reciprocal(n: Double) -> Double {
    return 1.0 / n
}

For log(base 10) just use the built-in log10(n: Double) -> Double