第七讲：Objective-C之Category

Sian

NSString+Reverse.h

1. #import <Foundation/Foundation.h>
2. @interface NSString(reverse)
3. - (NSString *) reverseString;
4. @end

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NSString+Reverse.m

1. #import <Foundation/Foundation.h>
2. #import "NSString+Reverse.h"
3. @implementation NSString (reverse){
4. - (id) reverseString{
5.      NSUinteger len = [self length];
6.      NSMutableString * retStr = [NSMutableString stringWithCapacity:len];
7.      while(len>0){
8.           unichar c = [self characterAtIndex:--len];
9.           NSString * str = [NSString stringWithFormat:@"%C",c];
10.           [retStr appendString:str];
11.          }
12.      return retStr;
13.      }
14. }
15. @end

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main.m

1. #import <Foundation/Foundation.h>
2. #import "NSString+Reverse.h"
3. int main(int argc, const char * argv[])
4. {
5.      NSAutoreleasePool = [[NSAutoreleasePool alloc] init];
6.      NSString * str = [NSString stringWithString:@"Hello World"];
7.      NSLog(@"String:%@",str);
8.      NSString * rev = [str reverseString];
9.      NSLog(@"Reversed:%@",rev);
10.      [pool drain];
11. }

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