iOS:制作一个简易的计算器

   初步接触视图,制作了一个简易的计算器,基本上简单的计算是没有问题的，不是很完美,可能还有一些bug,再接再厉。

//
//  ViewController.m
//  计算器
//
//  Created by ma c on 15/8/25.
//  Copyright (c) 2015年 bjsxt. All rights reserved.
//

#import "ViewController.h"

@interface ViewController ()
@property (weak, nonatomic) IBOutlet UITextField *ResultField;
@property(nonatomic,assign)CGFloat temp;
@property(nonatomic,assign)CGFloat num1;
@property(nonatomic,assign)CGFloat num2;
@property(nonatomic,strong)NSMutableString *string;
@property(nonatomic,strong)NSArray *arr;
@end
@implementation ViewController
- (IBAction)buttonClear:(UIButton *)sender
{
    [_string setString:@""];         //重新开始计算,文本框置空
    self.ResultField.text = _string;
}
- (IBAction)button7:(UIButton *)sender
{
    [_string appendString:@"7"];
    self.ResultField.text = _string;
}
- (IBAction)button8:(UIButton *)sender
{
    [_string appendString:@"8"];
    self.ResultField.text = _string;
}
- (IBAction)button9:(UIButton *)sender
{
    [_string appendString:@"9"];
    self.ResultField.text = _string;
}
- (IBAction)button4:(UIButton *)sender
{
    [_string appendString:@"4"];
    self.ResultField.text = _string;
}
- (IBAction)button5:(UIButton *)sender
{
    [_string appendString:@"5"];
    self.ResultField.text = _string;
}
- (IBAction)button6:(UIButton *)sender
{
    [_string appendString:@"6"];
    self.ResultField.text = _string;
}
- (IBAction)button1:(UIButton *)sender
{
    [_string appendString:@"1"];
    self.ResultField.text = _string;
}
- (IBAction)button3:(UIButton *)sender
{
    [_string appendString:@"3"];
    self.ResultField.text = _string;
}
- (IBAction)button2:(UIButton *)sender
{
    [_string appendString:@"2"];
    self.ResultField.text = _string;
}
- (IBAction)button0:(UIButton *)sender
{
    [_string appendString:@"0"];
    self.ResultField.text = _string;
}

- (IBAction)buttonPoint:(UIButton *)sender
{
    [_string appendString:@"."];
    self.ResultField.text = _string;
}

//触发算数运算事件
- (IBAction)buttonDiv:(UIButton *)sender
{
    [_string appendString:@"/"];
    self.ResultField.text = _string;
}

- (IBAction)buttonMul:(UIButton *)sender
{
    [_string appendString:@"*"];
    self.ResultField.text = _string;
}

- (IBAction)buttonSub:(UIButton *)sender
{
    [_string appendString:@"-"];
    self.ResultField.text = _string;
}

- (IBAction)buttonAdd:(UIButton *)sender
{
    [_string appendString:@"+"];
    self.ResultField.text = _string;
}

//做结果运算操作
- (IBAction)buttonEqual:(UIButton *)sender
{

    for(int i=0; i<[_string length]; i++)
    {
        
        self.arr = [[NSArray alloc]init];
        
        //只输入一个数,不做运算
        if([_string length] == 1)
        {
            self.temp = [_string doubleValue];
            break;
        }
        
        
        //做加法运算
        if([_string characterAtIndex:i] == '+')
        {
            self.arr = [_string componentsSeparatedByString:@"+"];
            
            self.num1 = [self.arr[0] doubleValue];
            self.num2 = [self.arr[1] doubleValue];
            self.temp = self.num1 + self.num2;
            break;
        }
        

        //做减法运算
        if([_string characterAtIndex:(i+1)] == '-')
        {
            self.arr = [_string componentsSeparatedByString:@"-"];
           
            if([self.arr count] == 2)
            {
                self.num1 = [self.arr[0] doubleValue];
                self.num2 = [self.arr[1] doubleValue];
                self.temp = self.num1 - self.num2;
            }
            else
            {
                self.num1 = [self.arr[1] doubleValue];
                self.num2 = [self.arr[2] doubleValue];
                self.temp = -(self.num1 + self.num2);
            }
            break;
        }
        
        
        //做除法运算
        if([_string characterAtIndex:i] == '/')
        {
            self.arr = [_string componentsSeparatedByString:@"/"];
            self.num1 = [self.arr[0] doubleValue];
            self.num2 = [self.arr[1] doubleValue];
            self.temp = self.num1 / self.num2;
            break;
        }
        
        //做乘法运算
        if([_string characterAtIndex:i] == '*')
        {
            self.arr = [_string componentsSeparatedByString:@"*"];
            self.num1 = [self.arr[0] doubleValue];
            self.num2 = [self.arr[1] doubleValue];
            self.temp = self.num1 * self.num2;
            break;
        }
        
    }
    
    //输出结果
    [_string setString:[NSString stringWithFormat:@"%.2f",self.temp]];
    self.ResultField.text = _string;
}

- (void)viewDidLoad {
    [super viewDidLoad];

    //创建一个可变的字符串
    _string = [NSMutableString stringWithCapacity:20];
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end