Merge pull request #102 from Sindhu-321/main

Added Sieve of eratosthenes algorithm

CPP/Sieve_of_Eratosthenes.cpp

@@ -0,0 +1,34 @@
+#include <iostream>
+
+using namespace std;
+#include <vector>
+
+vector<long long int> soe(long long int a){
+vector<bool> ref(a+1);
+vector<long long int> ans;
+int i=2;
+ans.push_back(2);
+while(i<=a){
+    for(int j=i*i;j<=a;j+=i){
+        if(!ref[j])ref[j]=true;
+    }
+    i++;
+    while(ref[i])i++;
+   if(i<=a) ans.push_back(i);
+
+}
+return ans;
+
+}
+
+int main()
+{
+    long long int n;
+    cout<<"enter number"<<endl;
+    cin>>n;
+    vector<long long int> primes=soe(n);
+    cout<<"The primes which are less than or equal to "<<n<<" are:"<<endl;
+    for(int i=0;i<primes.size();i++)cout<<primes[i]<<" ";
+    cout<<endl;
+
+}