Added Euclidean Algorithm in C++

Data Structure Algo/C++/euclidean_gcd.cpp

@@ -0,0 +1,25 @@
+#include <bits/stdc++.h>
+#define ll long long int
+using namespace std;
+ll num1, num2;
+
+ll gcd(ll a, ll b){
+    if (a==b) return a;
+    if (a<b) {
+        ll temp = a;
+        a = b;
+        b = temp;
+    }
+    while(b!=0 && a!=b){
+        b = b%a;
+        a = b;
+    }
+    return a;
+}
+int main(){
+    cout<<"Please Enter 2 numbers to find out their GCD: "<<endl;
+    cin>>num1>>num2;
+    ll result = gcd(num1, num2);
+    cout<<"The GCD of "<<num1<<" and "<<num2<<" is: "<<result<<endl;
+    return 0;
+}