Question

Guided Assignment Problem 3: Call Stack

Your Tasks:

Answer the following questions. Include a function stack chart/diagram for each question to verify your answers.

1. Use a call stack to explain the result of calling example(3).

   int example(int n) {

     if (n == 0)

   return 0;

     else

   return example(n – 1) + n * n * n;

   }

2. Use a call stack to explain how many time(s) the method factorial invokes itself with an argument of 5 of factorial(5).

   int factorial(int n) {

     if (n == 0)

       return 1;

     else

       return (n * factorial(n – 1));

   }

3. Include the following items in the same Word file for the final submission:
   • Your responses to the two tasks listed above

Answer 1

1. example(3)

This function finally returns 36 that can be seen from the below diagram:

example(3) calls 2, 2 calls 1, and 1 calls 0, finally example(0) returns 0 and the values are computed as shown in the figure above. Then example(1) returns 1, example(2) adds 8 to 1 and returns 9, and finally example(3) adds 9 to 27 and returns 36 as the final ans.

2. Factorial(5)

After factorial(5) is invoked, method factorial invokes itself 5 times more as shown:

When call reaches factorial(0), it starts to return values. 1 is returned to factorial(1), which again returns 1 to factorial(2), it then returns 2 to factorial(3), which returns 6 to factorial(4), which returns 24 to factorial(5), which then finally returns the final answer as 24*5 = 120