Recursion Function

Which of the following is the best definition of a RECURSIVE method?

• A method that iterates itself exactly 5 times.

• A method that cannot be called more than once.

• A method that invokes itself by name within the method.

• A method that will never iterate infinitely.

Every line in a C program should end with a _______

• ;

• :

• ,

• .

Commonly used input function is _____

• scanf()

• printf()

• total()

• above all

The process in which a function calls itself directly or indirectly is called _______

The method copies the address of an argument/ parameter into the formal parameter is call by ______

The code given shows a function namely print_message to print out a message. The code in red box is a function declaration which is also known as function ______

• function prototype

• function call

• function definition

• above all

Guess the output?

• 3

• 18

• 6

• Error

Answer explanation

The recursion case defined in the nSum() function of the above example is:

int res = n + nSum(n - 1)

The base condition defined for nSum() function is:

if (n = = 0) {

return 0;

}

In the nSum() function, Recursive Case is:

int res = n + nSum(n - 1);

In the program, n = 3, so as nSum(3)'s recursive case, we get:

int res = 3 + nSum(2);

In nSum(2), the recursion case will be the same, but n = 2, so nSum(2) will be:

int res = 2 + nSum(1);

Similarly, for nSum1:

int res = 1 + nSum(0);

As such, for nSum(3), we get:

int res = 3 + 2 + 1 + nSum(0);

As the base condition is n == 0, nSum(0) will return 0.

So the recursion will stop here and the final value returned by the function will be:

int res = 3 + 2 + 1 + 0;

= 0

Factorial of a positive integer (number) is the sum of multiplication of all the integers smaller than that positive integer.

Based on the code given, what is the factorial of given positive integer?

Answer explanation

Algorithm of Factorial Program:

1. 1. Start program

2. 2. n1 is initialize as 5

3. 3. 5 is passed to the formal variable in findFactorial() function

4. 4. From 5 until 1, multiple each digit and update the final value

5. 5. The final value in main() function will be f = 5*4*3*1

6. 6. f = 120

7. 7. End program

The program given prompt an input of a sentence. Given sentence is TODAY IS MONDAY. What will be the output

Answer explanation

1. 1. When the sentence TODAY IS MONDAY is keyed-in, the reverseSentence() function is invoked/ called.

2. 2. reverseSentence() function stores the first letter entered in C. If the variable is any character other than newline (/n), reverseSentence() function is invoked again.

3. 3. This process will be repeated until /n is discovered (when ENTER key is hit).

4. 4. So, when /n is detected, the reverseSentence() function starts printing characters from last.

Choose a correct statement about C Function?

• By default, return 0 is added as the last statement of a function without specific return type

• main() is default function in C

• Every Function may not have a return value

• All the above