Move file to Math directory

Math/sieve_of_Eratosthenes.cpp

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+/*
+ * Sieve of Eratosthenes is an algorithm to find the primes 
+ * that is between 2 to N (as defined in main).
+ *
+ * Time Complexity  : O(N * log N)
+ * Space Complexity : O(N)
+ */
+
+#include <iostream>
+using namespace std;
+
+#define MAX 10000000
+
+int isprime[MAX];
+
+/*
+ * This is the function that finds the primes and eliminates 
+ * the multiples.
+ */
+void sieve(int N) {
+    isprime[0] = 0;
+    isprime[1] = 0;
+    for (int i = 2; i <= N; i++) {
+        if (isprime[i]) {
+            for (int j = i * 2; j <= N; j += i) {
+                isprime[j] = 0;
+            }
+        }
+    }
+}
+
+/*
+ * This function prints out the primes to STDOUT
+ */
+void print(int N) {
+    for (int i = 1; i <= N; i++) {
+        if (isprime[i] == 1) {
+            cout << i << ' ';
+        }
+    }
+    cout << '\n';
+}
+
+/*
+ * NOTE: This function is important for the 
+ * initialization of the array.
+ */
+void init() {
+    for (int i = 1; i < MAX; i++) {
+        isprime[i] = 1;
+    }
+}
+
+int main() {
+    int N = 100;
+    init();
+    sieve(N);
+    print(N);
+}