ACM Primes

Write a program to read in a list of integers and determine whether or not each number is prime. A number, n, is prime if its only divisors are 1 and n. For this problem, the numbers 1 and 2 are not considered primes. 

InputEach input line contains a single integer. The list of integers is terminated with a number<= 0. You may assume that the input contains at most 250 numbers and each number is less than or equal to 16000. 
OutputThe output should consists of one line for every number, where each line first lists the problem number, followed by a colon and space, followed by "yes" or "no". 
Sample Input

1
2
3
4
5
17
0

Sample Output

1: no
2: no
3: yes
4: no
5: yes
6: yes

 1 #include<bits/stdc++.h>
 2 using namespace  std;
 3 const int MAX = 16005;
 4 int prime[MAX];
 5 void init()
 6 {
 7     memset(prime,0,sizeof(prime));
 8     prime[1] = 2; //非素数
 9     for(int i = 2; i < MAX; i++) /*先建立一个素数表*/
10     {
11         if(prime[i] == 0)
12         {
13             prime[i] = 1;
14             for(int j = i *2; j < MAX; j+=i)
15                 prime[j] = 2;
16         }
17     }
18     prime[2] = 2;
19 }
20 int main()
21 {
22     init();
23     int temp = 0,n;
24     while(cin>>n)
25     {
26         if(n <= 0)
27             break;
28         if(prime[n] == 2)    //非素数
29             cout<< ++temp <<": no"<<endl;
30         else    //素数
31             cout<< ++temp <<": yes"<<endl;
32     }
33 
34     return 0;
35 }

 

转载于:https://www.cnblogs.com/jj81/p/7356853.html