diff --git a/100N.cpp b/100N.cpp
new file mode 100644
index 0000000..c5bab1e
--- /dev/null
+++ b/100N.cpp
@@ -0,0 +1,13 @@
+#include <iostream>
+
+using namespace std;
+
+int main()
+{
+    static int i=1;
+    if (i<= 100)
+       {
+          cout<<i++<<" ";
+          main();
+       }
+}
diff --git a/design.cpp b/design.cpp
new file mode 100644
index 0000000..2580231
--- /dev/null
+++ b/design.cpp
@@ -0,0 +1,25 @@
+#include <iostream>
+
+using namespace std;
+
+int main()
+{
+   int a;
+   cout<<"Enter the No. of Rows"<<endl;
+   cin>>a;
+   for ( int i=1; i<=a; i++)
+   {
+       int c;
+       c= a-i;
+       for (int j=1; j<=c; j++)
+       {
+         cout<<" ";
+       }
+      for (int k=0; k<i; k++)
+          {
+              cout<<"#";
+          }
+        cout<<endl;
+   }
+
+}
diff --git a/divisible by 5&11.cpp b/divisible by 5&11.cpp
new file mode 100644
index 0000000..4d7a141
--- /dev/null
+++ b/divisible by 5&11.cpp	
@@ -0,0 +1,40 @@
+#include <iostream>
+
+using namespace std;
+
+int main()
+{
+    /*int a;
+    cout<<"Enter a number to see either it is divisible by 5 and 11 or not.\n";
+    cin>>a;
+    if (a%5)
+    {
+        (a%11)? cout<<"The number is neither divisible by 5 nor 11.\n" : cout<<"The Number is Only divisible by 11.\n";
+    }
+    else
+    {
+        (a%11)? cout<<"The number is only divisible by 5.\n" : cout<<"The number is divisible by both 5 nor 11.\n";
+    }*/
+   int a,b,c;
+   cout<<"enter two number \n";
+   cin>>a>>b;
+   cout<<"1. for addition\n 2. for substraction\n 3 for multiolication\n 4 for division\n";
+   cin>>c;
+   switch(c)
+   {
+   case 1:
+        cout<<"add is "<<a+b;
+        break;
+   case 2:
+        cout<<"substraction is "<<a-b;
+         break;
+   case 3:
+        cout<<"multiplaction is "<<a*b;
+        break;
+   case 4:
+        cout<<"division is "<<a/b;
+        break;
+   default:
+        cout<<"invalid input";
+   }
+}