Added armstrong number program.

Dynamic Programming/Armstrong Number.cpp

@@ -0,0 +1,20 @@
+//program to check whether a number is an armstrong number or not
+#include<iostream.h>
+#include<Math.h>
+int main()
+{
+  int n,k,d,s=0;
+  cout<<"Enter a number:";
+  cin>>n;
+  k=n;
+  while(k!=0)
+  {
+    d=k%10;
+    s+=(int)pow(d,3);
+    k/=10;
+  }
+  if(s==n)
+   cout<<n<<"is an armstrong number";
+  else
+   cout<<n<<"is not an armstrong number";
+}