[IOS programming] Simple calculator

더하기, 빼기, 나누기 연산 가능한 간단한 계산기입니다.

 

 

import UIKit

class ViewController: UIViewController {

    
    @IBOutlet weak var notice: UILabel!
    
    @IBOutlet weak var number_A: UITextField!
    
    @IBOutlet weak var operator_symbol: UILabel!
    
    @IBOutlet weak var number_B: UITextField!
    
    @IBOutlet weak var result: UITextField!
    
    var num_A_string:String = ""
    var num_B_string:String = ""
    
    var number_A_decimal:Float = 0
    var number_B_decimal:Float = 0
    var number_Result_decimal:Float = 0
    
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
    }

    @IBAction func click_Sum(_ sender: UIButton) {
        //step 1
        //convert text to decimal numbers
        result.text = ""
        num_A_string = number_A.text!
        num_B_string = number_B.text!
        
        if ((!num_A_string.isEmpty) && (!num_B_string.isEmpty))
        {
            let number_A_decimal = Float(num_A_string)
            let number_B_decimal = Float(num_B_string)
        
        //step 2
        //process summation
            number_Result_decimal = number_A_decimal! + number_B_decimal!
        
        //step 3
        //covert Result to text and display
            result.text = String(number_Result_decimal)
        
            operator_symbol.text = "+"
        }
        
        else{
            //case 1: both numbers are empty
            if(num_A_string.isEmpty && num_B_string.isEmpty)
            {
                notice.text = "Insert number A and B"
            }
            
            //case 2: number A is empty
            else if (num_A_string.isEmpty){
                
                notice.text = "Insert number A"
            }
            
            //case 3: number B is empty                                                                                                                                                                                                                                           
            else{
                
                notice.text = "Insert number B"
            }
        }
    }
    
    @IBAction func click_Sub(_ sender: UIButton) {
        //step 1
        //convert text to decimal numbers
        result.text = ""
        num_A_string = number_A.text!
        num_B_string = number_B.text!
        
        if ((!num_A_string.isEmpty) && (!num_B_string.isEmpty))
        {
            let number_A_decimal = Float(num_A_string)
            let number_B_decimal = Float(num_B_string)
        
        //step 2
        //process summation
            number_Result_decimal = number_A_decimal! - number_B_decimal!
        
        //step 3
        //covert Result to text and display
            result.text = String(number_Result_decimal)
        
            operator_symbol.text = "-"
        }
        
        else{
            //case 1: both numbers are empty
            if(num_A_string.isEmpty && num_B_string.isEmpty)
            {
                notice.text = "Insert number A and B"
            }
            
            //case 2: number A is empty
            else if (num_A_string.isEmpty){
                
                notice.text = "Insert number A"
            }
            
            //case 3: number B is empty
            else{
                
                notice.text = "Insert number B"
            }
        }
    }
    
    @IBAction func click_Div(_ sender: Any) {
        //step 1
        //convert text to decimal numbers
        result.text = ""
        num_A_string = number_A.text!
        num_B_string = number_B.text!
        
        if ((!num_A_string.isEmpty) && (!num_B_string.isEmpty))
        {
            let number_A_decimal = Float(num_A_string)
            let number_B_decimal = Float(num_B_string)
        
            if (number_B_decimal != 0){
                //step 2
                //process summation
                    number_Result_decimal = number_A_decimal! / number_B_decimal!
                
                //step 3
                //covert Result to text and display
                    result.text = String(number_Result_decimal)
                
                    operator_symbol.text = "/"
            }
            else{
                notice.text = "Cannot divide by 0"
            }
       
        }
        
        else{
            //case 1: both numbers are empty
            if(num_A_string.isEmpty && num_B_string.isEmpty)
            {
                notice.text = "Insert number A and B"
            }
            
            //case 2: number A is empty
            else if (num_A_string.isEmpty){
                
                notice.text = "Insert number A"
            }
            
            //case 3: number B is empty
            else{
                
                notice.text = "Insert number B"
            }
        }
    }
    
}