#include <iostream>
#include <cstdio>
signed main()
{
	double p=1.0/3;int i=4,u=p*i,v=i-p*i;
	std::cout<<u<<" "<<v;
}

输出：

1 2

若是

#include <iostream>
#include <cstdio>
signed main()
{
	double p=1.0/3;int i=4,u=p*i,v=i-u;
	std::cout<<u<<" "<<v;
}

则输出：

1 3

萌新求教