CMU 15-112: Fundamentals of Programming and Computer Science
Extra Practice for Week 2 (Due never) Code Tracing (CT) Exercises

1. def ct1(s, t): result = "" for c in s: if (c.upper() not in "NO!!!"): i = t.find(c) if (result != ""): result += ":" result += f"{i}{c}{s[i]}{t[i]}" return result print(ct1("net", "two"))


2. def ct2(s): result = "" d = ord("a") for c in s.lower(): if (c.isalpha() and (ord(c) >= d)): result += str(ord(c) - d) + chr(d) d += 1 return result print(ct2("Be a CA?!?"))


3. def ct3(s): result = "" while (len(s) > 1): result += s[:1] + s[2:4] + "." s = s[1:-1:2] return result + s print(ct3("abcdefghi"))


4. def ct4(s, n): result = "" d = 0 while (n > 0) and (len(s) > 0): if (s[-1].isdigit()): result += str((n%10)%int(s[-1])) else: result += chr(ord('D')+d) n //= 10 s = s[1:-1] d += 1 return result print(ct4("abc3c3", 2468))