Two unsigned types want to subtract the result stored temporary variable or unsigned type

1#include <stdio.h>2 intMain ()3 {4UnsignedintDwval =0;5unsigned __int64 n64val =1;6     if(Dwval-n64val >= -)7     {8printf"%i64d\n", Dwval-n64val);//execute this line, output-19     }Ten     return 0; One}

Personal analysis:

When you do want to reduce the operation (Dwval-n64val), the Dwval and N64val are converted to unsigned __int64,
The two want to reduce the result is-1, storage for 0xFFFFFFFFFFFFFFFF, as unsigned __int64 use
Compared to the following number (20), the result of the calculation is true, and the result of the printout is the __int64 type
The corresponding value is-1

Further verification:

1#include <iostream>2 intMain ()3 {4UnsignedintDwval =0;5unsigned __int64 n64val =1;6unsigned __int64 N64val2 =0xffffffffffffffff;7     if(Dwval-n64val >=n64val2)8     {9printf"%i64d\n", Dwval-n64val);//execute this line, output-1Ten     } OneN64val2 = Dwval-n64val;//N64val2 = 0xffffffffffffffff ASystem"Pause"); -     return 0; -}

1#include <iostream>2 intMain ()3 {4UnsignedintDwval =0;5unsigned __int64 n64val =2;6unsigned __int64 N64val2 =0xffffffffffffffff;7     if(Dwval-n64val >=n64val2)8     {9printf"%i64d\n", Dwval-n64val);//Do not get hereTen     } OneN64val2 = Dwval-n64val;//N64val2 = 0xfffffffffffffffe, less than N64val2 ASystem"Pause"); -     return 0; -}

Thoughts on GetTickCount () 49.7 days after counting zero

_logtick = :: GetTickCount64 ();     // dosomething;    if (:: GetTickCount ()-_logtick >= Log_tick_max)    {        printf ("%i64d\n",:: GetTickCount ()- _logtick);    }

Two unsigned types want to subtract the result stored temporary variable or unsigned type