Added BMI calculator

Basic-Scripts/bmi_calc.py

@@ -0,0 +1,33 @@
+#!/usr/bin/env python3.7
+
+# BMI = (weight in kg / height in meters squared)
+
+def gather_info():
+    height = float(input("What is your height? (inches or meters) "))
+    weight = float(input("What is your weight? (pounds or kilograms) "))
+    system = input("Are your measurements in metric or imperial units? ").lower().strip()
+    return (height, weight, system)
+
+def calculate_bmi(weight, height, system='metric'):
+    """
+    Return the Body Mass Index (BMI) for the
+    given weight, height, and measurement system.
+    """
+    if system == 'metric':
+        bmi = (weight / (height ** 2))
+    else:
+        bmi = 703 * (weight / (height ** 2))
+    return bmi
+
+while True:
+    height, weight, system = gather_info()
+    if system.startswith('i'):
+        bmi = calculate_bmi(weight, system='imperial', height=height)
+        print(f"Your BMI is {bmi}")
+        break
+    elif system.startswith('m'):
+        bmi = calculate_bmi(weight, height)
+        print(f"Your BMI is {bmi}")
+        break
+    else:
+        print("Error: Unknown measurement system. Please use imperial or metric.")