a007. 判斷質數 | From: [180.218.173.249] | 發表日期 : 2015-03-25 18:56

#include <iostream>

#include <math.h>

#define max 4795

void findprime(int prime[max])

{

long a,b,c,d,e=0;

int flag=0;

prime[e++]=2;

prime[e++]=3;

prime[e++]=5;

prime[e++]=7;

prime[e++]=11;

prime[e++]=13;

a=15;

while(e<max)

{

flag=0;

c=(int)sqrt(a);

for(b=1;b<=c;b++)

{

if(a%prime[b]==0)

flag=1;

break;

}

if(flag==0)

prime[e++]=a;

a+=2;

}

}

using namespace std;

int main()

{

int a[max],s,d,f;

findprime(a);

while(cin>>s)

{

d=0;

for(f=0;f<3000;f++)

{

if(s==a[f])

{

d=1;

cout<<"質數"<<endl; 

break;

}

}

if(d==0)

cout<<"非質數"<<endl;

}

return 0;

}