使用Objective-C 計算代碼已耗用時間，objective-c代碼

使用Objective-C 計算代碼已耗用時間，objective-c代碼
第一種：（最簡單的NSDate）

NSDate* tmpStartData = [NSDate date];//You code here...double deltaTime = [[NSDate date] timeIntervalSinceDate:tmpStartData];NSLog(@"cost time = %f", deltaTime);

第二種：（將運行代碼放入下面的Block中，返回時間）

#import <mach/mach_time.h>  // for mach_absolute_time() and friends    CGFloat BNRTimeBlock (void (^block)(void)) {      mach_timebase_info_data_t info;      if (mach_timebase_info(&info) != KERN_SUCCESS) return -1.0;        uint64_t start = mach_absolute_time ();      block ();      uint64_t end = mach_absolute_time ();      uint64_t elapsed = end - start;        uint64_t nanos = elapsed * info.numer / info.denom;      return (CGFloat)nanos / NSEC_PER_SEC;  }

第三種：

/** * 計算指令碼時間 * @param $last 最後一次的運行clock * @param $key  標識 * @return 當前clock */double t(double last, char* key){    clock_t now = clock();    printf("time:%fs \t key:%s \n", (last != 0) ? (double)(now - last) / CLOCKS_PER_SEC : 0, key);    return now;}double t1 = t(0, "");//do somethingt(t1, "end");