判断一段内存是否全部为0

方法一：

        start = clock();
	while( (BITSIZE-sizeof(int)*index)>=sizeof(int) )
	{
		//printf("%d %d\t",( *(int *)((char*)bits+sizeof(int)*index) ),(*(bits+index)));
		//result |= ( *(int *)((char*)bits+sizeof(int)*index) );
		result |= ( *(bits+index) );
		index++;
	}
	if(result==0)
		printf("bits is all 0!\n");
	else
		printf("bits is not all 0!\n");
	finish = clock();
	printf( "%d %d %d tick\n",start,finish, finish - start );

 

方法二：

        start = clock();
	while(  (BITSIZE-sizeof(int)*index)>=sizeof(int)  )
	{
		if( *(bits+index)==0 )
		{
			index++;
			continue;
		}
		else
			break;
	}
	if(index==(BITSIZE/sizeof(int)))
		printf("bits is all 0!\n");
	else
		printf("bits is not all 0!\n");
	finish = clock();
        printf( "%d %d %d tick\n",start,finish, finish - start );

 

  方法一和方法二的效率基本一致