sieve_of_erastothenes.java

sieve_of_erastothenes.java

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+
+class SieveOfEratosthenes
+{
+	void sieveOfEratosthenes(int n)
+	{
+		boolean prime[] = new boolean[n+1];
+		for(int i=0;i<=n;i++)
+			prime[i] = true;
+
+		for(int p = 2; p*p <=n; p++)
+		{
+			// If prime[p] is not changed, then it is a prime
+			if(prime[p] == true)
+			{
+				// Update all multiples of p
+				for(int i = p*p; i <= n; i += p)
+					prime[i] = false;
+			}
+		}
+
+		// Print all prime numbers
+		for(int i = 2; i <= n; i++)
+		{
+			if(prime[i] == true)
+				System.out.print(i + " ");
+		}
+	}
+
+	// Driver Program to test above function
+	public static void main(String args[])
+	{
+		int n = 30;
+		System.out.print("Following are the prime numbers ");
+		System.out.println("smaller than or equal to " + n);
+		SieveOfEratosthenes g = new SieveOfEratosthenes();
+		g.sieveOfEratosthenes(n);
+	}
+}
+