Title: There is such a clever expression:
a^=b^=a^=b;
It does not require temporary variables can exchange the values of a and b.
[ Answer ]
This is not portable. It attempts to modify variables twice a sequence of points in between, and this behavior is undefined. For example, it was reported the following code:
int a=123,b=7654;
a^=b^=a^=b;
In the SCO optimizing C compiler will set to 123 b, the a is set to 0.
Title: takes an integer from 4 to 7 from the right end of a.
【answer】
main()
{
unsigned a,b,c,d;
scanf("%o",&a);
b=a>>4;
c=~(~0<<4);
d=b&c;
printf("%o\n%o\n",a,d);
}Title: x a statement implemented to judge whether a power of 2.
【answer】
void mai n()
{
i nt a;
scanf(“%d”,&a);
printf(“%c”,(a)&(a-1)?’n’:’y’); // 若是打印y，否则n
}Topic: Please return the following value (Microsoft) function
int fun(x)
{
int countx=0;
while(x)
{
countx++;
x=x&(x-1);
}
return countx;
}Assuming x = 9999.
【answer】
8