Day 21 Euclid and Seive of Erastothenes

Author: akshatprogrammer

Other Basic/Euclids.cpp

@@ -0,0 +1,38 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+
+// Euclids Algo
+int gcd(int a,int b){
+    if(b==0) return a;
+
+    return gcd(b,a%b);
+}
+
+// Seive Of Erastothenes
+
+vector<bool> seiveOfErastothenes(int n){
+    vector<bool> isprime(n+1,true);
+   // memset(isprime,sizeof(isprime),true);
+    isprime[0]=false;
+    isprime[1]=false;
+
+    for(int i=2;i*i<=n;i++){
+            for(int j=2*i;j<=n;j+=i){
+                isprime[j]=false;
+            }
+    }
+    return isprime;
+}
+
+int main(){
+    int n=20;
+    vector<bool> isprime=seiveOfErastothenes(n);
+    for(int i=1;i<=n;i++){
+        cout << i << " " << isprime[i] << endl;
+    }
+
+    int a=24,b=60;
+    cout << "GCD of 24 and 60 is " << gcd(24,60) << endl;
+    return 0;
+}