Add erathosthenesSieve

Added the implementation of the erathostenes sieve in golang. This implementation can find primes numbers up to 10e7 in a deterministic way

Author: Andres Francisco Villegas Pelaez

eratosthenesSieve.go

@@ -0,0 +1,38 @@
+package main
+
+import (
+	"fmt"
+)
+
+//Only works for primes smaller or equal to 10e7
+func sieve(upperBound int64) []int64 {
+	_sieveSize := upperBound + 10
+	//Creates set to mark wich numbers are primes and wich are not
+	//true: not primes, false: primes
+	//this to favor default initialization of arrays in go
+	var bs [10000010]bool
+	//creates a slice to save the primes it finds
+	primes := make([]int64, 0, 1000)
+	
+	bs[0] = true
+	bs[1] = true
+	//iterate over the numbers set
+	for i := int64(0); i <= _sieveSize; i++ {
+		//if find one number that is not marked as a compund number, mark all its multiples
+		if !bs[i] {
+			for j := i * i; j <= _sieveSize; j += i {
+				bs[j] = true
+			}
+			//Add the prime you just find to the slice of primes
+			primes = append(primes, i)
+		}
+	}
+	return primes
+}
+
+func main() {
+	//prints first N primes into console
+	N := 100
+	primes := sieve(N)
+	fmt.Println(primes)
+}