我目前正在通过“大书呆子牧场”一书学习objective-c。我重复了第 18 章中的代码，但我遇到了错误。使用 64 位 macos 10.6 巫婆实际版本的 xcode。
编译器说：
构建目标 BMITime
CompileC /Users/pm/Library/Developer/Xcode/DerivedData/BMITime-cjqpmtvlmdoeiecyxbofznzjgpij/Build/Intermediates/BMITime.build/Debug/BMITime.build/Objects-normal/x86_64/main.o BMITime/main.m normal x86_64 目标- c com.apple.compilers.llvm.clang.1_0.compiler cd /Users/pm/Dropbox/objective-c/BMITime setenv LANG en_US.US-ASCII /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault。xctoolchain/usr/bin/clang -x objective-c -arch x86_64 -fmessage-length=0 -std=gnu99 -fobjc-arc -Wno-trigraphs -fpascal-strings -O0 -Wno-missing-field-initializers -Wno-缺少原型 -Wreturn-type -Wno-implicit-atomic-properties -Wformat -Wno-missing-braces -W括号 -Wswitch -Wno-unused-function -Wno-unused-label -Wno-unused-parameter -Wunused-variable - Wunused-value -Wuninitialized -Wno-unknown-pragmas -Wno-shadow -Wno-four-char-constants -Wno-sign-compare -Wshorten-64-to-32 -Wpointer-sign -Wno-newline-eof -Wno-选择器 -Wno-strict-selector-match -Wno-undeclared-selector -Wno-deprecated-implementations -DDEBUG=1 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10。 7.sdk -fasm-blocks -Wprotocol -Wdeprecated-declarations -mmacosx-version-min=10。7 -g -Wno-conversion -Wno-sign-conversion "-DIBOutlet=属性((iboutlet))" "-DIBOutletCollection(ClassName)=属性((iboutletcollection(ClassName)))" "-DIBAction=void)属性((ibaction)" -iquote /Users/pm/Library/Developer/Xcode/DerivedData/BMITime-cjqpmtvlmdoeiecyxbofznzjgpij/Build/Intermediates/BMITime.build/Debug/BMITime.build/BMITime-generated-files.hmap -I/Users/ pm/Library/Developer/Xcode/DerivedData/BMITime-cjqpmtvlmdoeiecyxbofznzjgpij/Build/Intermediates/BMITime.build/Debug/BMITime.build/BMITime-own-target-headers.hmap -I/Users/pm/Library/Developer/Xcode/ DerivedData/BMITime-cjqpmtvlmdoeiecyxbofznzjgpij/Build/Intermediates/BMITime.build/Debug/BMITime.build/BMITime-all-target-headers.hmap -iquote /Users/pm/Library/Developer/Xcode/DerivedData/BMITime-cjqpmtvlmdoeiecyxbofznzjgpij/Build/中间体/BMITime.build/Debug/BMITime.build/BMITime-project-headers。hmap -I/Users/pm/Library/Developer/Xcode/DerivedData/BMITime-cjqpmtvlmdoeiecyxbofznzjgpij/Build/Products/Debug/include -I/Users/pm/Library/Developer/Xcode/DerivedData/BMITime-cjqpmtvlmdoeiecyxbofznzjgpij/Build/Intermediates/ BMITime.build/Debug/BMITime.build/DerivedSources/x86_64 -I/Users/pm/Library/Developer/Xcode/DerivedData/BMITime-cjqpmtvlmdoeiecyxbofznzjgpij/Build/Intermediates/BMITime.build/Debug/BMITime.build/DerivedSources -F/ Users/pm/Library/Developer/Xcode/DerivedData/BMITime-cjqpmtvlmdoeiecyxbofznzjgpij/Build/Products/Debug -include /Users/pm/Library/Developer/Xcode/DerivedData/BMITime-cjqpmtvlmdoeiecyxbofznzjgpij/Build/Intermediates/PrecompiledHeaders/BMITime-Prefix- bbjacqhmgaerfrhblktcvkpzzntb/BMITime-前缀。pch -MMD -MT 依赖项 -MF /Users/pm/Library/Developer/Xcode/DerivedData/BMITime-cjqpmtvlmdoeiecyxbofznzjgpij/Build/Intermediates/BMITime.build/Debug/BMITime.build/Objects-normal/x86_64/main.d --序列化诊断 /Users/pm/Library/Developer/Xcode/DerivedData/BMITime-cjqpmtvlmdoeiecyxbofznzjgpij/Build/Intermediates/BMITime.build/Debug/BMITime.build/Objects-normal/x86_64/main.dia -c /Users/pm/ Dropbox/objective-c/BMITime/BMITime/main.m -o /Users/pm/Library/Developer/Xcode/DerivedData/BMITime-cjqpmtvlmdoeiecyxbofznzjgpij/Build/Intermediates/BMITime.build/Debug/BMITime.build/Objects-normal/ x86_64/main.obuild/Objects-normal/x86_64/main.dia -c /Users/pm/Dropbox/objective-c/BMITime/BMITime/main.m -o /Users/pm/Library/Developer/Xcode/DerivedData/BMITime-cjqpmtvlmdoeiecyxbofznzjgpij/构建/中间体/BMITime.build/Debug/BMITime.build/Objects-normal/x86_64/main.obuild/Objects-normal/x86_64/main.dia -c /Users/pm/Dropbox/objective-c/BMITime/BMITime/main.m -o /Users/pm/Library/Developer/Xcode/DerivedData/BMITime-cjqpmtvlmdoeiecyxbofznzjgpij/构建/中间体/BMITime.build/Debug/BMITime.build/Objects-normal/x86_64/main.o
/Users/pm/Dropbox/objective-c/BMITime/BMITime/main.m:21:10: 错误：'Employee' 没有可见的@interface 声明选择器'setWeightInKilos:' [person setWeightInKilos:96]；^ /Users/pm/Dropbox/objective-c/BMITime/BMITime/main.m:22:10: 错误：'Employee' 没有可见的@interface 声明选择器'setHeightInMeters:' [person setHeightInMeters:1.8]；^ /Users/pm/Dropbox/objective-c/BMITime/BMITime/main.m:26:22: 错误：'Employee' 没有可见的@interface 声明选择器'bodyMassIndex' float bmi = [person bodyMassIndex]; ^ 产生 3 个错误。
我的代码如下所示：
主文件
#import <Foundation/Foundation.h>
#import "Employee.h"
int main(int argc, const char * argv[])
{
@autoreleasepool {
// Erstellt eine Instanz von Person
Employee *person = [[Employee alloc] init];
// Gibt den Instanzvariablen interessante Werte
[person setWeightInKilos:96];
[person setHeightInMeters:1.8];
[person setEmployeeID:15];
// Ruft die Methode bodyMassIndex auf
float bmi = [person bodyMassIndex];
NSLog(@"Employee %d has a BMI of %f", [person employeeID], bmi);
}
return 0;
}
人.h
#import <Foundation/Foundation.h>
// Die Klasse Person erbt alle Instanzvariablen
// und Methoden, die von der Klasse NSObject definiert wurden
@interface Person : NSObject
{
// Sie hat zwei Instanzvariablen
float heightInMeters;
int weightInKilos;
}
@property float heightInMeters;
@property int weightInKilos;
// Diese Methode berechnet den Body-Mass-Index
- (float)bodyMassIndex;
@end
员工.h
#import <Foundation/Foundation.h>
#import "Person.h"
@interface Employee : NSObject
{
int employeeID;
}
@property int employeeID;
@end
员工.m
#import "Employee.h"
@implementation Employee
@synthesize employeeID;
@end
人.m
#import "Person.h"
@implementation Person
@synthesize heightInMeters, weightInKilos;
- (float)bodyMassIndex
{
//return weightInKilos / (heightInMeters * heightInMeters);
float h = [self heightInMeters];
return [self weightInKilos] / (h * h);
}
@end