摘要:[Objective-C]基礎語法Example
這篇筆記只是單純的把TutorialsPoint的Objective-C教學的Example摘取下來，若想要了解更多訊息，可連至該網站-TutorialsPoint的Objective-C教學。個人覺得還滿簡單清楚的。
基本Syntax
宣告Variable
Example
/* variable definition: */
int a, b;
int c;
float f;
/* actual initialization */
a = 10;
b = 20;
宣告Constants
Example
const int LENGTH = 10;
const int WIDTH = 5;
const char NEWLINE = '\n';
for迴圈
Example
int a;
for( a = 10; a < 20; a = a + 1 )
{
NSLog(@"value of a: %d\n", a);
}
while迴圈
Example
int a = 10;
while( a < 20 )
{
NSLog(@"value of a: %d\n", a);
a++;
}
switch
Example
char grade = 'B';
switch(grade)
{
case 'A' :
NSLog(@"Excellent!\n" );
break;
case 'B' :
case 'C' :
NSLog(@"Well done\n" );
break;
case 'D' :
NSLog(@"You passed\n" );
break;
case 'F' :
NSLog(@"Better try again\n" );
break;
default :
NSLog(@"Invalid grade\n" );
}
Function
Example-Function定義
- (int) max:(int) num1 secondNumber:(int) num2
{
/* local variable declaration */
int result;
if (num1 > num2)
{
result = num1;
}
else
{
result = num2;
}
return result;
}
Example-Function叫用
int a = 100;
int b = 200;
int ret;
SampleClass *sampleClass = [[SampleClass alloc]init];
/* calling a method to get max value */
ret = [sampleClass max:a andNum2:b];
Array
Example-宣告陣列
double balance[10];
Example-初始化陣列
double balance[5] = {1000.0, 2.0, 3.4, 17.0, 50.0};
Block
Block語法
returntype (^blockName)(argumentType);
Example
void (^simpleBlock)(void) = ^{
NSLog(@"This is a block");
};
帶參數與回傳值
double (^multiplyTwoValues)(double, double) =
^(double firstValue, double secondValue) {
return firstValue * secondValue;
};
double result = multiplyTwoValues(2,4);
NSLog(@"The result is %f", result);
物件導向Syntax
Object & Class
Example
#import <Foundation/Foundation.h>
@interface SampleClass:NSObject
- (void)sampleMethod;
+ (void)sampleClassMethod;
@end
@implementation SampleClass
- (void)sampleMethod{
NSLog(@"Hello, World! \n");
}
+ (void)sampleClassMethod{
NSLog(@"class(static) method!");
}
@end
int main()
{
SampleClass *sampleClassObj = [[SampleClass alloc]init];
[sampleClassObj sampleMethod];
[SampleClass sampleClassMethod];
return 0;
}
屬性
Example
@interface Person : NSObjects
@property(nonatomic, readwrite) double height;
@end
@implementation Person
@synthesize height;
@end
Protocol
Syntax-宣告Protocol
@protocol ProtocolName
@required
// list of required methods
@optional
// list of optional methods
@end
Example-宣告Protocol
@protocol PrintProtocolDelegate
- (void)processCompleted;
@end
Syntax-採用Protocol
@interface MyClass : NSObject <MyProtocol>
...
@end
Example-採用Protocol
@interface SampleClass:NSObject<PrintProtocolDelegate>
@end
@implementation SampleClass
-(void)processCompleted{
NSLog(@"Printing Process Completed");
}
@end
Category
Syntax
@interface ClassName (CategoryName)
@end
Example
@interface NSString(MyAdditions)
+(NSString *)getCopyRightString;
@end
@implementation NSString(MyAdditions)
+(NSString *)getGreetString{
return @"Hello";
}
@end
int main(int argc, const char * argv[])
{
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
NSString *greeting = [NSString getGreetString];
NSLog(@"Accessing Category: %@",greeting);
[pool drain];
return 0;
}
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