How to exchange two values without a variable? Here are some solutions:

void swap1(int& a,int& b)
{
	a^=b;
	b^=a;
	a^=b;
}

void swap2(int& a,int& b)
{
	a=a+b;
	b=a-b;
	a=a-b;
}

void swap3(int& a,int& b)
{
	a=a-b;
	b=a+b;
	a=b-a;
}

__asm{
    xchg val1,val2
}

# python
a, b = b, a