Objective c 键值编码符合性

我很愚蠢，没有按照编程的方式持续测试，所以现在我不确定错误是从哪里来的。我在做一个可编程计算器。当我运行时，它会在显示任何内容之前崩溃，并向我显示以下消息：

*** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<CalculatorViewController 0x6a405a0> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key description.'

这是CalculatorBrain.m:

#import "CalculatorBrain.h"

@interface CalculatorBrain()
@property (nonatomic, strong) NSMutableArray *programStack;
@property (nonatomic,strong)NSDictionary *variableValues;
@end

@implementation CalculatorBrain

@synthesize programStack = _programStack;
@synthesize variableValues = _variableValues;

- (NSMutableArray *)programStack
{
if (!_programStack) _programStack = [[NSMutableArray alloc] init];
return _programStack;
}

- (id)program
{
return [self.programStack copy];
}


//Here are the two types of pushes that the ViewController can implement.  First, operand pushes . . . 

- (void)pushOperand:(double)operand
{
[self.programStack addObject:[NSNumber numberWithDouble:operand]];
}


//. . . and then variable pushes.

- (void) pushOperandAsVariable:(NSString *)variable
{
//Create dictionary
//Move this later on to ViewController but for now leave where it is....
NSMutableArray *variablesUsed = [[NSMutableArray alloc] init];
NSArray *objects = [[NSArray alloc] initWithObjects:[NSNumber numberWithDouble:3],[NSNumber numberWithDouble:4.1],[NSNumber numberWithDouble:-6],[NSNumber numberWithDouble:4.5298], [NSNumber numberWithDouble:3.14159], nil];
NSArray *keys = [[NSArray alloc] initWithObjects:@"x",@"y",@"z",@"foo", @"π", nil];
NSDictionary *variableValues = [[NSDictionary alloc] initWithObjects:objects forKeys:keys];

//Check program for keys
    NSNumber *operand;
for (int i=0; i<keys.count; i++)
{
    if ([[keys objectAtIndex:i] isEqual:variable])
        [variablesUsed addObject:variable];
    operand = [variableValues objectForKey:variable];
}
[self.programStack addObject:operand];
}

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

+ (double)popOffStack:(NSMutableArray *)stack
{
double result = 0;
id topOfStack = [stack lastObject];
if (topOfStack) [stack removeLastObject];
if ([topOfStack isKindOfClass:[NSNumber class]])
{
    result = [topOfStack doubleValue];
}

//Here are the results for various operations.

else if ([topOfStack isKindOfClass:[NSString class]])
{
    NSString *operation = topOfStack;
    if ([operation isEqualToString:@"+"]) 
    {
        result = [self popOffStack:stack] +
        [self popOffStack:stack];
    } 
    else if ([@"*" isEqualToString:operation]) 
    {
        result = [self popOffStack:stack] *
        [self popOffStack:stack];
    } 
    else if ([operation isEqualToString:@"-"]) 
    {
        double subtrahend = [self popOffStack:stack];
        result = [self popOffStack:stack] - subtrahend;
    } 
    else if ([operation isEqualToString:@"/"]) 
    {
        double divisor = [self popOffStack:stack];
        if (divisor) result = [self popOffStack:stack] / divisor;
    }
    else if ([operation isEqualToString:@"sin"])
    {
        result = sin([self popOffStack:stack]);
    }
    else if ([operation isEqualToString:@"cos"])
    {
        result = cos([self popOffStack:stack]);
    }
    else if ([operation isEqualToString:@"√"])
    {
        result = sqrt([self popOffStack:stack]);
    }
    else if ([operation isEqualToString:@"π"])
    {
        result = M_PI;
    }
}
return result;
}

+ (double)runProgram:(id)program
{
//Run program.
NSMutableArray *mutableCopyOfProgram;
if ([program isKindOfClass:[NSArray class]]) 
{
    mutableCopyOfProgram = [program mutableCopy];

return [self popOffStack:mutableCopyOfProgram];
}
else return 0;
}

@end

#导入“CalculatorBrain.h”
@接口计算器Brain（）
@属性（非原子，强）NSMutableArray*programStack；
@属性（非原子，强）NSDictionary*可变值；
@结束
@实现计算器Brain
@综合程序堆栈=_程序堆栈；
@综合可变值=_可变值；
-（NSMutableArray*）程序堆栈
{
如果（！\u programStack）\u programStack=[[NSMutableArray alloc]init]；
返回程序栈；
}
-（id）方案
{
返回[self.programStack copy]；
}
//以下是ViewController可以实现的两种推送类型。首先，操作数推送。
-（无效）操作数：（双）操作数
{
[self.programStack addObject:[NSNumber numberWithDouble:操作数]]；
}
//. . . 然后是可变推力。
-（void）pushOperationAsVariable:（NSString*）变量
{
//创建字典
//稍后将其移动到ViewController，但现在请保留其位置。。。。
NSMutableArray*variablesUsed=[[NSMutableArray alloc]init]；
NSArray*对象=[[NSArray alloc]initWithObjects:[NSNumber numberWithDouble:3]，[NSNumber numberWithDouble:4.1]，[NSNumber numberWithDouble:-6]，[NSNumber numberWithDouble:4.5298]，[NSNumber numberWithDouble:3.14159]，无]；
NSArray*keys=[[NSArray alloc]initWithObjects:@“x”@“y”@“z”@“foo”@“π”，nil]；
NSDictionary*variableValues=[[NSDictionary alloc]initWithObjects:objects forKeys:keys]；
//检查程序中的键
NSNumber*操作数；
对于（int i=0；i而言，最常见的原因是在故事板或xib文件中定义了一个
CalculatorViewController
对象，图形界面中有一个指向其上一个名为“description”的出口的链接。同时，您在该课程的代码中不再有
说明
出口

这通常会通过在interface builder中跟踪并删除错误的引用来解决。
最常见的原因是您在序列图像板或xib文件中定义了一个
CalculatorViewController
对象，图形界面中的某个对象有一个指向其上名为“描述”的出口的链接。同时，您在该课程的代码中不再有
说明
出口

这通常会通过在interface builder中跟踪并删除错误的引用来解决。
是的。这就解决了它。我将
description
重命名为
descriptionLabel
，但一开始还没有删除
description
。是的。这就解决了它。我将
description
重命名为
desScriptionLabel
但一开始还没有摆脱
描述
。。。。
#import "CalculatorBrain.h"

@interface CalculatorBrain()
@property (nonatomic, strong) NSMutableArray *programStack;
@property (nonatomic,strong)NSDictionary *variableValues;
@end

@implementation CalculatorBrain

@synthesize programStack = _programStack;
@synthesize variableValues = _variableValues;

- (NSMutableArray *)programStack
{
if (!_programStack) _programStack = [[NSMutableArray alloc] init];
return _programStack;
}

- (id)program
{
return [self.programStack copy];
}


//Here are the two types of pushes that the ViewController can implement.  First, operand pushes . . . 

- (void)pushOperand:(double)operand
{
[self.programStack addObject:[NSNumber numberWithDouble:operand]];
}


//. . . and then variable pushes.

- (void) pushOperandAsVariable:(NSString *)variable
{
//Create dictionary
//Move this later on to ViewController but for now leave where it is....
NSMutableArray *variablesUsed = [[NSMutableArray alloc] init];
NSArray *objects = [[NSArray alloc] initWithObjects:[NSNumber numberWithDouble:3],[NSNumber numberWithDouble:4.1],[NSNumber numberWithDouble:-6],[NSNumber numberWithDouble:4.5298], [NSNumber numberWithDouble:3.14159], nil];
NSArray *keys = [[NSArray alloc] initWithObjects:@"x",@"y",@"z",@"foo", @"π", nil];
NSDictionary *variableValues = [[NSDictionary alloc] initWithObjects:objects forKeys:keys];

//Check program for keys
    NSNumber *operand;
for (int i=0; i<keys.count; i++)
{
    if ([[keys objectAtIndex:i] isEqual:variable])
        [variablesUsed addObject:variable];
    operand = [variableValues objectForKey:variable];
}
[self.programStack addObject:operand];
}

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

+ (double)popOffStack:(NSMutableArray *)stack
{
double result = 0;
id topOfStack = [stack lastObject];
if (topOfStack) [stack removeLastObject];
if ([topOfStack isKindOfClass:[NSNumber class]])
{
    result = [topOfStack doubleValue];
}

//Here are the results for various operations.

else if ([topOfStack isKindOfClass:[NSString class]])
{
    NSString *operation = topOfStack;
    if ([operation isEqualToString:@"+"]) 
    {
        result = [self popOffStack:stack] +
        [self popOffStack:stack];
    } 
    else if ([@"*" isEqualToString:operation]) 
    {
        result = [self popOffStack:stack] *
        [self popOffStack:stack];
    } 
    else if ([operation isEqualToString:@"-"]) 
    {
        double subtrahend = [self popOffStack:stack];
        result = [self popOffStack:stack] - subtrahend;
    } 
    else if ([operation isEqualToString:@"/"]) 
    {
        double divisor = [self popOffStack:stack];
        if (divisor) result = [self popOffStack:stack] / divisor;
    }
    else if ([operation isEqualToString:@"sin"])
    {
        result = sin([self popOffStack:stack]);
    }
    else if ([operation isEqualToString:@"cos"])
    {
        result = cos([self popOffStack:stack]);
    }
    else if ([operation isEqualToString:@"√"])
    {
        result = sqrt([self popOffStack:stack]);
    }
    else if ([operation isEqualToString:@"π"])
    {
        result = M_PI;
    }
}
return result;
}

+ (double)runProgram:(id)program
{
//Run program.
NSMutableArray *mutableCopyOfProgram;
if ([program isKindOfClass:[NSArray class]]) 
{
    mutableCopyOfProgram = [program mutableCopy];

return [self popOffStack:mutableCopyOfProgram];
}
else return 0;
}

@end