poj 3006 Dirichlet's Theorem on Arithmetic Progressions

 1 #include <cstdio>
 2 
 3 int isPrime(int n)
 4 {
 5     if(n == 1 || (n != 2 && n % 2 == 0))
 6         return 0;
 7     for(int i = 2; i*i <= n; ++i)
 8         if(n%i == 0)
 9             return 0;
10     return 1;
11 }
12 
13 int main()
14 {
15     int a,d,n,cun,temp;
16     while(scanf("%d %d %d",&a,&d,&n) && a && d && n)
17     {
18         cun = 0;
19         for(int i = 0; cun != n; ++i)
20         {
21             temp = a + i*d;
22             if(isPrime(temp))
23                 ++cun;
24         }
25         printf("%d\n",temp);
26     }
27     return 0;
28 }