poj 2262 Goldbach's Conjecture

#include<iostream>
using namespace std;
const int MAX=1000000;
bool isprime[MAX+1];
int prime[MAX];
int pnum;
void getprime()
{
int i,j;
memset(isprime,0,sizeof(isprime));
pnum=0;
for(i=2;i<=MAX;i++)
{
if(!isprime[i])
prime[pnum++]=i;
for(j=0;j<pnum&&prime[j]*i<=MAX;j++)
{
isprime[prime[j]*i]=1;
if(i%prime[j]==0) break;
}
}
isprime[0]=1;isprime[1]=1;
}
int main()
{
int n,s,e;
getprime();
while(scanf("%d",&n),n)
{
s=3,e=n-3;
while(1)
{
if(!isprime[s] && !isprime[e])
{
printf("%d = %d + %d/n", n,s,e);
break;
}
else
s+=2,e-=2;
}
}
return 0;
}