Sieve of Eratosthenes Algorithm

Sieve/sieve.c

@@ -0,0 +1,36 @@
+//This code compute the list of primes between 2 and N - 1 using the sieve algorithm that runs in O(nlogn)
+#include <stdio.h>
+
+#define N	100010
+int is_composite[N];
+int sz = 0;
+int primes[N];
+
+void sieve(){
+	for(int i = 2 ; i * i < N ; i++){//Run until square root of N
+		if(!is_composite[i]){//if 'i' is a prime number then mark all multiples of 'i' as a composite number
+			for(int j = i + i ; j < N ; j += i){
+				is_composite[j] = 1;
+			}
+		}
+	}
+
+	for(int i = 2 ; i < N ; i++){
+		if(!is_composite[i]){
+			primes[sz++] = i;
+		}
+	}
+}
+
+int main(){
+	sieve();
+
+	printf("we have %d primes between(2..%d)\n", sz, N - 1);
+	printf("Showing the 40 first primes....:\n");
+
+	for(int i = 0 ; i < 40 ; i++){
+		printf("%d\n", primes[i]);
+	}
+
+	return 0;
+}