From 8b330ac4392ab61fd9d3fca296e162182c7aa4f9 Mon Sep 17 00:00:00 2001
From: yugantar99 <73051921+yugantar99@users.noreply.github.com>
Date: Sun, 18 Oct 2020 12:37:13 +0530
Subject: [PATCH] sieve.cpp

Finding prime numbers in nloglogn complexity
---
 C++/sieve.cpp | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)
 create mode 100644 C++/sieve.cpp

diff --git a/C++/sieve.cpp b/C++/sieve.cpp
new file mode 100644
index 0000000..f3617fe
--- /dev/null
+++ b/C++/sieve.cpp
@@ -0,0 +1,32 @@
+//Program to find the prime numbers in O(nloglogn)
+#include <bits/stdc++.h> 
+using namespace std; 
+  
+void SieveOfEratosthenes(int n) 
+{ 
+    bool prime[n+1]; 
+    memset(prime, true, sizeof(prime)); 
+  
+    for (int p=2; p*p<=n; p++) 
+    { 
+        if (prime[p] == true) 
+        { 
+            for (int i=p*p; i<=n; i += p) 
+                prime[i] = false; 
+        } 
+    } 
+  
+    for (int p=2; p<=n; p++) 
+       if (prime[p]) 
+          cout << p << " "; 
+} 
+  
+// Driver Program 
+int main() 
+{ 
+    int n = 1000; 
+    cout << "Here are the prime numbers smaller "
+         << " than or equal to " << n << endl; 
+    SieveOfEratosthenes(n); 
+    return 0; 
+}