update,

max015/CDS2003_assignment02/src/P07.py

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+'''
+Draft a python script to solve the following questions. thanks
+
+# Requirement
+Please use recursion to define and test a function to check whether a number is Prime or not.
+
+# procedure
+- let's think it step by step
+- leave me comment with your code
+- solve with recursion
+- write your code in `def isPrime_Recur(a,b):` , with comment `# implementation here`
+- write a sample function to use it, with comment `# test here`
+'''
+
+import sys
+sys.setrecursionlimit(999999)
+
+
+def isPrime_Recur(a,b):
+    # implementation here
+
+    # https://t5k.org/notes/faq/negative_primes.html
+    if a < 0:
+        return "tested number should be greater than 1"
+
+    # https://corp.tutorocean.com/is-1-a-prime-number/
+    if a == 0 or a == 1:
+        return "Conservative result: tested number is neither prime nor composite"
+
+    if b == 1:
+        return True
+
+    if a % b == 0:
+        return False
+    else:
+        return isPrime_Recur(a,b-1)
+
+# test here
+if __name__ == '__main__':
+    num_list = [-99, -3, -1, 0, 1, 3, 7, 9, 9999, 10007]
+    for num in num_list:
+        print('is ', num, ' Prime?', isPrime_Recur(num, num-1))
+