### trim NSString

    
    
    NSString * string = @"\n \t\t hello string  \t\n  \n\n";
    NSString * trimed = [string stringByTrimmingCharactersInSet:
                 [NSCharacterSet whitespaceAndNewlineCharacterSet]]
    NSLog(@"%@", trimed);

trim 一个 NSString

### 一个简单的 MD5加密算法:

    
    
    #import 
    #import 
    
    @interface MD5 : NSobject 
    {
    } 
    -(NSString *)MD5:(NSString *)string;
    @end
    
    @implementation MD5
    
    -(NSString *)MD5:(NSString *)string
    {
        const char *src = [[string lowercaseString] UTF8String];
        unsigned char result[CC_MD5_DIGEST_LENGTH];
        CC_MD5(src, strlen(src), result);
        NSString * ret = [NSString stringWithFormat:@"%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X",
                          result[0], result[1], result[2], result[3],
                          result[4], result[5], result[6], result[7],
                          result[8], result[9], result[10], result[11],
                          result[12], result[13], result[14], result[15]];
        return ret;
    }
    @end

trim 一个 NSString

Objective-c MD5加密

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