Current File : //usr/share/doc/bc-1.06.95/Examples/twins.b
/* An example that finds all primes between 2 and limit. */
define primes (limit) {
auto num, p, root, i
prime[1] = 2;
prime[2] = 3;
num = 2;
scale = 0;
for ( p=5; p <= limit; p += 2) {
root = sqrt(p);
isprime = 1;
for ( i = 1; i < num && prime[i] <= root; i++ ) {
if ( p % prime[i] == 0 ) {
isprime = 0;
break;
}
}
if (isprime) {
num += 1;
prime [num] = p;
}
}
}
print "\ntyping 'twins (10)' will print all twin primes less than 10.\n"
define twins (limit) {
auto i;
i = primes(limit+2);
for (i=1; prime[i] > 0; i++) {
if ((prime[i]+2) == prime[i+1]) \
print "twins are ", prime[i], " and ", prime[i+1], "\n"
}
}
Mini Shell