Sum of primes in odd positions is prime: Difference between revisions

=={{header|C}}==

<lang c>#include<stdio.h>

#include<stdlib.h>

int isprime( int p ) {

int i;

if(p==2) return 1;

if(!(p%2)) return 0;

for(i=3; i*i<=p; i+=2) {

if(!(p%i)) return 0;

}

return 1;

}

int main( void ) {

int s=0, p, i=1;

for(p=2;p<=999;p++) {

if(isprime(p)) {

if(i%2) {

s+=p;

if(isprime(s)) printf( "%d %d %d\n", i, p, s );

}

i+=1;

}

}

return 0;

}</lang>