Exam 2 – Comments and Solutions

\(\boxdot\) Problem 3

• Example solution:

  def switch_pairs(l_in, n):
      if len(l_in) != 2*n:
          return l_in
      for i in range(0, len(l_in)-1, 2):
          l_in[i], l_in[i+1] = l_in[i+1], l_in[i]
      return l_in

\(\boxdot\) Problem 4

• Example solution:

  def print_triangle(n):
      for i in range(n):
          print('*'*(i+1))
      for i in range(n-1,0,-1):
          print('*'*i)  

\(\boxdot\) Problem 5

• Code for tracing:

  def func1(l, m):
      x = 0
      m = 3
      for i in range(len(l)):
          x = x + l[i]*m
          l[i] = x
      print(m)
      print(l)
      print(x)
      return x
  
  
  def main():
      x = 4
      k = [0]
      for i in range(x):
          k.append(i)
      m = func1(k, x)
      print(m)
      print(x)
      print(k)
  
  
  main()