Added Sieve of Eratosthenes Algorithm

Added Sieve of Eratosthenes Algorithm written in C++.

Author: divakar-lakhera

.gitignore

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+
+.vs/cs-algorithms/v16/Browse.VC.db
+.vs/cs-algorithms/v16/Browse.VC.opendb
+.vs/ProjectSettings.json
+.vs/slnx.sqlite
+.vs/cs-algorithms/v16/ipch/AutoPCH/cf84f1c192b8b4da/SIEVEOFERATOSTHENES.ipch

Sieve of Eratosthenes/SieveOfEratosthenes.cpp

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+#include <iostream>
+#include <string>
+using namespace std;
+/*
+Sieve of Eratosthenes
+
+Compiled Using Visual Studio 2019
+by Divakar Lakhera
+*/
+
+/*
+		char* sieveOfEratosthenes(int limit)
+			- returns char* buffer of size "limit+1" with all the positions marked "1" for primes.
+			- returns NULL if "limit" is set to "0".
+*/
+
+char* sieveOfEratosthenes(int limit)
+{
+	if (limit != 0) {
+		char* buf = (char*)malloc(sizeof(char) * (limit + 1));
+		if (buf == NULL)
+		{
+			cout << "Fatal: Internal error \"Cannot Malloc\" " << endl;
+			exit(-1);
+		}
+		memset(buf, 1, limit + 1);
+
+		for (int i = 2; i * i <= limit; i++)
+		{
+			if (buf[i] == 1)
+			{
+				for (int j = i * i; j <= limit; j += i)
+				{
+					buf[j] = 0;
+				}
+			}
+		}
+		return buf;
+	}
+	else
+	{
+		return NULL;
+	}
+}
+
+
+void dispPrimes(int limit)
+{
+
+	char* a = sieveOfEratosthenes(limit);
+	if (a != NULL) {
+		for (int i = 2; i < limit; i++)
+		{
+			if (a[i] == 1)
+			{
+				cout << i << " ";
+			}
+		}
+	}
+	else
+	{
+		cout << "ERROR: Limit Set to 0" << endl;
+	}
+}
+
+int main()
+{
+	dispPrimes(100);
+	return 0;
+}