Create largest.py

have just added the largest number program hope it helps.

Day01-15/code/Day05/largest.py

@@ -0,0 +1,19 @@
+``` Given an array, find the largest element in it.
+
+Input : arr[] = {10, 20, 4}
+Output : 20
+
+Input : arr[] = {20, 10, 20, 4, 100}
+Output : 100  ```
+  
+  def largest(arr,n): 
+    max = arr[0]
+    for i in range(1, n):
+        if arr[i] > max:
+            max = arr[i]
+    return max
+  
+arr = [10, 324, 45, 90, 9808]
+n = len(arr)
+Ans = largest(arr,n)
+print ("Largest in given array is",Ans)