素数的筛选和bool类型的妙用

 1 #include<iostream>
 2 using namespace std;
 3 #define max  10000
 4 bool num[10002];
 5 int pan1,pan2;
 6 void foundprime(){
 7     for(int i=2;i<=100;i++)
 8     {
 9         for(int j=i*i;j<=max;j+=i)
10         {    if(num[j]==true)
11                 num[j]=false;
12         }
13     }
14 }
15 void   chazhao(int number){
16     for(int i=2;i<=number/2;i++)
17     {
18         if(num[i]==true)
19         {
20             if(num[number-i]==true)
21             {
22
23                 pan1=i;pan2=number-i;
24             }
25         }
26     }
27 }
28
29
30 int main()
31 {   int number;
32
33      memset(num,true, sizeof(num));
34      num[0]=num[1]=false;
35       foundprime();
36     while(scanf("%d",&number)!=EOF)
37     {
38
39      chazhao(number);
40      cout<<pan1<<" "<<pan2<<endl;
41     }
42     return 0;
43 }