IOS基础开发二（iphone计算器）

今天做了个iphone的小例子计算器：才用mvc设计模式

项目目录：

代码如下：

CalculatorViewController：(MVC的控制器)

//  CalculatorViewController.h
//  Calculator
//
//  Created by WildCat on 13-7-28.
//  Copyright (c) 2013年 wildcat. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface CalculatorViewController : UIViewController
@property (weak, nonatomic) IBOutlet UILabel *display;

@end

//
//  CalculatorViewController.m
//  Calculator
//
//  Created by WildCat on 13-7-28.
//  Copyright (c) 2013年 wildcat. All rights reserved.
//

#import "CalculatorViewController.h"
#import "CalculatorBrain.h"

@interface CalculatorViewController()
@property (nonatomic) BOOL userIsinTheMiddleOfEnteringANumber;
@property(nonatomic,strong)CalculatorBrain *brain;
@end

@implementation CalculatorViewController
@synthesize display=_display;

@synthesize userIsinTheMiddleOfEnteringANumber=_userIsinTheMiddleOfEnteringANumber;

@synthesize brain=_brain;
-(CalculatorBrain *)brain{
    if(!_brain) _brain=[[CalculatorBrain alloc] init];
    return _brain;

}

- (IBAction)digitPressed:(UIButton *)sender {
    NSString *digit=[sender currentTitle];
    //建一个局部变量

    if (self.userIsinTheMiddleOfEnteringANumber) {

        self.display.text=[self.display.text stringByAppendingString:digit];
    }else{
        self.display.text=digit;
        self.userIsinTheMiddleOfEnteringANumber=YES;
    }

}
- (IBAction)operationPressed:(UIButton *)sender {

    if ([self userIsinTheMiddleOfEnteringANumber]) {
        [self enterPressed];
    }
    double result=[self.brain performOperation:sender.currentTitle];

    NSString *resultString=[NSString stringWithFormat:@"%g",result];
    self.display.text=resultString;

}
- (IBAction)enterPressed {

    [self.brain pushOperand:[self.display.text doubleValue]];
    self.userIsinTheMiddleOfEnteringANumber=NO;

}
- (IBAction)enterDEL:(id)sender {
    NSString *nowstr=self.display.text;
    int len=nowstr.length;
    int nowlength=len-1;
    if (nowlength>=1) {
        self.display.text=[nowstr substringWithRange:NSMakeRange(0, nowlength)];

    }else{
        self.display.text=@"0";
    }

}

@end


CalculatorBrain(计算器大脑mvc中的model)
//  CalculatorBrain.h
//  Calculator
//
//  Created by WildCat on 13-7-28.
//  Copyright (c) 2013年 wildcat. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface CalculatorBrain : NSObject
-(void)pushOperand:(double)operand;
-(double)performOperation:(NSString *)operation;

@property (readonly)id program;
+(double) runProgram:(id) program;
+(NSString *)discriptionOfProgram:(id) program;

@end


//
//  CalculatorBrain.m
//  Calculator
//
//  Created by WildCat on 13-7-28.
//  Copyright (c) 2013年 wildcat. All rights reserved.
//

#import "CalculatorBrain.h"
//定义一个私有的栈
@interface CalculatorBrain()
@property (nonatomic,strong)NSMutableArray *programStack;
@end

@implementation CalculatorBrain
@synthesize programStack=_programStack;
//ProgramStack的setter and  getter............
-(NSMutableArray *)programStack{
    if (_programStack==nil) {
        _programStack=[[NSMutableArray alloc] init];
    }
    return _programStack;
}
-(void)setProgramStack:(NSMutableArray *)programStack{
    _programStack=programStack;
}

-(double)performOperation:(NSString *)operation{
    [self.programStack addObject:operation];
    return [CalculatorBrain runProgram:self.program];

}
-(id)program{

    return [self.programStack copy];
}
//入栈
-(void)pushOperand:(double)operand{

    [self.programStack addObject:[NSNumber numberWithDouble:operand]];

}
//出栈
-(double)popOperand{
    NSNumber *number=[self.programStack lastObject];
    if (number) {
        [self.programStack removeLastObject];
    }
    return [number doubleValue];

}
+(double)popOperandOffStack:(NSMutableArray *)stack{
    double result=0;
    id topOfStack=[stack lastObject];
    if (topOfStack) {
        [stack removeLastObject];
    }
    if ([topOfStack isKindOfClass:[NSNumber class]]){
        result=[topOfStack doubleValue];
    }else if ([topOfStack isKindOfClass:[NSString class]]){
        NSString*operation=topOfStack;
        if ([@"+" isEqualToString:operation]) {
            result=[self popOperandOffStack:stack]+[self popOperandOffStack:stack];
        }else if ([@"*" isEqualToString:operation]){
            result=[self popOperandOffStack:stack]*[self popOperandOffStack:stack];
        }else if ([@"-" isEqualToString:operation]){

            double firstnumber=[self popOperandOffStack:stack];
            double secondnumber=[self popOperandOffStack:stack];
            result=secondnumber-firstnumber;
        }else if([@"/" isEqualToString:operation]){
            double firstnumber=[self popOperandOffStack:stack];
            double secondnumber=[self popOperandOffStack:stack];
            if(firstnumber)result=secondnumber/firstnumber;
        }

    }
    return result;

}
+(double) runProgram:(id) program{
    NSMutableArray *stack;
    if ([program isKindOfClass:[NSArray class]]) {
        stack=[program mutableCopy];
    }

    return [self popOperandOffStack:stack];
}
+(NSString *)discriptionOfProgram:(id) program{

    return @"Implament this in Assignment2";
}

@end

效果图：