Objective-C几种字符串处理速度的测试数据

转载自：http://www.cocoachina.com/bbs/read.php?tid-17652-fpage-9.html

仅供参考  
测试机器 2.4 GHz Intel Core 2Duo    2GB 667 MHz DDR2   GCC 4.2

- (void)testStringSpeed:(id)sender {     NSAutoreleasePool *pool=[[NSAutoreleasePool alloc] init];     [textField setStringValue:@""];     int testi,testnum=10;     float c,tm=0.0;     for(testi=0;testi<testnum;testi++){         NSDate *beg=[NSDate date];         int i,n=10000000;         for(i=0;i<n;i++){             //avg=0.030204             /*             {                 //avg=0.594266 内存基本稳定不变                 NSString *t=[[NSString alloc] initWithString:@"abccc"];                 [t release];             }*/                          /*             {                 //avg=0.026101 内存基本稳定不变                 NSString *astring = @"abcc";             }*/                          /*             {                 //avg=0.278873 内存基本稳定不变                 NSString *astring = [[NSString alloc] init];                 astring = @"abcc";                 [astring release];             }*/                          /*             {                 //avg=2.737541 内存基本稳定不变                 char *Cstring = "abcc";                 NSString *astring = [[NSString alloc] initWithCString:Cstring];                 [astring release];             }*/                          /*             {                 //avg=3.619728 内存增长过快                 NSString *a=[NSString stringWithString:@"abcc"];             }*/                          /*             {                 //太长时间，内存增长过快                 NSString *a=[NSString stringWithFormat:@"abcc%d",i];             }              */                          /*             {                 //avg=0.034632   内存基本稳定不变                 char a[]="abcc";             }*/                                       /*             {                 //18.1555  内存稍有增长                 NSString *a=[[NSString alloc] initWithFormat:@"abcc%d",i];                 [a release];             }*/                          /*             {                 //avg=2.276076   内存基本稳定不变                 char a[32];                 sprintf(a,"abcc%d",i);             }*/                          /*             {                 //太长时间，内存增长过快                 NSMutableString *a=[[NSMutableString alloc] init];                 [a stringByAppendingFormat:@"abcc%d",i];                 [a release];             }*/         }         c=[[NSDate date] timeIntervalSinceDate:beg];         tm+=c;         [textField setStringValue:[NSString stringWithFormat:@"%@\n%d=%f",[textField stringValue],testi+1,c]];     }     [textField setStringValue:[NSString stringWithFormat:@"%@\navg=%f",[textField stringValue],(float)tm/testnum]];     [pool release]; }