add print method to Body object

lib/class.py

@@ -1,20 +1,25 @@
-import numpy as np
-
+#!/usr/bin/python
+# -*- coding:utf-8 -*-
 """
 Class definition for physical atribute
 """
+import numpy as np
 
 
 class Body:
     
-
-    
     def __init__(self, mass, position, velocity):
         self.m = mass
         self.q = position
         self.v = velocity
         self.p = velocity*mass
 
+    def __repr__(self): # Called upon "print(body)"
+        return "Body of mass: {0:.2f}kg, position: {1}, velocity: {2}".format(self.m, self.p, self.v)
+    
+    def __str__(self): # Called upon "str(body)"
+        return "Body of mass: {0:.2f}kg, position: {1}, velocity: {2}".format(self.m, self.p, self.v)
+
 
 class System:
 
@@ -49,8 +54,7 @@ class System:
         return L
 
 
-    #def initialize(self):
-
+if __name__ == "__main__":        
     # initialisation mass
     m1 = 10
     m2 = 1
@@ -82,4 +86,3 @@ tribody = System([star1,star2,star3])
     print("list=",Lbodylist)
 
     print(tribody.Lval(Lbodylist))
-