Question

The following questions are on recursion in C++ Programming.

I had some trouble with these questions, can you please help me? Thank you!

Consider the following recursive function

void funcEx8(int u, char v) //Line 1

{ //Line 2

if (u == 0) //Line 3

cout << u << " "; //Line 4

else //Line 5

{ //Line 6

int x = static_cast (v); //Line 7

if (v < 'A') //Line 8

v = static_cast (x + 1); //Line 9

else if (v > 'Z') //Line 10

v = static_cast (x - 1); //Line 11

cout << v << " "; //Line 12

funcEx8(u - 2, v); //Line 13 }

//Line 14 }

//Line 15 }

Identify the base case? Using line numbers

	a.	Lines 3,4
	b.	Lines 1 through 4
	c.	Lines 7,8
	d.	Lines 5,6

Consider the following recursive function

void funcEx8(int u, char v) //Line 1

{ //Line 2

if (u == 0) //Line 3

cout << u << " "; //Line 4

else //Line 5

{ //Line 6

int x = static_cast (v); //Line 7

if (v < 'A') //Line 8

v = static_cast (x + 1); //Line 9

else if (v > 'Z') //Line 10

v = static_cast (x - 1); //Line 11

cout << v << " "; //Line 12

funcEx8(u - 2, v); //Line 13 }

//Line 14 }

//Line 15 }

Identify the Recursive case? Using line numbers

	a.	Lines 5 Through 15
	b.	Lines 3,4
	c.	1,2
	d.	Lines 2,3

Consider the following recursive function

void funcEx8(int u, char v) //Line 1

{ //Line 2

if (u == 0) //Line 3

cout << u << " "; //Line 4

else //Line 5

{ //Line 6

int x = static_cast (v); //Line 7

if (v < 'A') //Line 8

v = static_cast (x + 1); //Line 9

else if (v > 'Z') //Line 10

v = static_cast (x - 1); //Line 11

cout << v << " "; //Line 12

funcEx8(u - 2, v); //Line 13 }

//Line 14 }

//Line 15 }

Valid or Invalid

funcEx8(26, '$'); is a valid call,

	a.	None
	b.	Yes and No
	c.	No
	d.	Yes

Consider the following recursive function:

void recFun(int u)

{

if (u == 0) cout << "Zero! ";

else

{

cout << "Negative ";

recFun(u + 1);

}

}

what is the output if recFun(8)

	a.	Infinite loop, nonegative
	b.	5
	c.	0
	d.	8

Consider the following recursive function:

void recFun(int u)

{

if (u == 0) cout << "Zero! ";

else

{

cout << "Negative ";

recFun(u + 1);

}

}

. what is the output if recFun(0)

	a.	12
	b.	infinite loop
	c.	8
	d.	zero

Consider the following recursive function:

void recFun(int u)

{

if (u == 0) cout << "Zero! ";

else

{

cout << "Negative ";

recFun(u + 1);

}

}

. what is the output if recFun(-2)

	a.	8
	b.	Negative Negative Zero!
	c.	-2
	d.	zero

Consider the following recursive function:

void recFun(int x)

{

if (x > 0)

{ cout << x % 10 << " ";

recFun(x / 10);

}

else

if (x != 0)

cout << x << endl;

}

what is the output of the above statement if recFun(258)?

	a.	12
	b.	3 4 6
	c.	15
	d.	8     5       2

Consider the following recursive function:

void recFun(int x)

{

if (x > 0)

{ cout << x % 10 << " ";

recFun(x / 10);

}

else

if (x != 0)

cout << x << endl;

}

. what is the output of the above statement if recFun(7)?

	a.	7
	b.	8
	c.	8   5     2
	d.	12

Consider the following recursive function:

void recFun(int x)

{

if (x > 0)

{ cout << x % 10 << " ";

recFun(x / 10);

}

else

if (x != 0)

cout << x << endl;

}

what is the output of the above statement if recFun(36)?

	a.	5 3 8
	b.	12
	c.	6 3
	d.	2 4 5

Consider the following recursive function:

void recFun(int x)

{

if (x > 0)

{ cout << x % 10 << " ";

recFun(x / 10);

}

else

if (x != 0)

cout << x << endl;

}

what is the output of the above statement if recFun(-85)?

	a.	12
	b.	-85
	c.	8     5    2
	d.	85

Answer 1

Q1)

Answer is Option A

In Recursive Function the best case is when the recursive part didn't run and the function ends . So In the given function if u is 0 then it ends just by printing u so it is the best case

Q2)

Answer is Option A

Recursive Part starts from line 5 when if condition is False and it comes in else part and then it starts the recursion under else part .

Q3)

Answer is Option D

Function needs two parameters i.e. one Int and other is Char So we pass 26 as Int and '$' as char . So Yes it is valid call

Q4)

Answer is Option A

As In recursion we are incrementing u by 1 each time so it will never become 0 and recursion only ends when u is 0 . So It goes in infinite loop

Q5)

Answer is Option D

The passes argument is 0 so if condition i.e. u==0 is true so we print the output Zero and function ends

Q6)

Answer is Option D

Now as u <0 So first else is true so negative will print and function is call by making -2 + 1= -1 So Again else is true and negative printed . Now u =0 hence we print zero

So Output is Negative Negative Zero

Q7)

Answer is Option D

Lets see how function will run

We have x = 258

First x% 10 = 8 is printed and x = 258/10 = 25

Second  x% 10 = 5 is printed and x = 25/10 = 2

At last x %10 = 2 and x= 2/10 = 0

Now Both If and else if is false  so function ends

Hence Output is 8 5 2

Q8)

Answer is Option A

Similarly as we do in last part Again x = 7

So x % 10 = 7 and x /10 = 0

Now Both If and else if is false  so function ends

Hence Output is 7

Q9)

Answer is Option C

Now x = 36

So x%10 = 6 and print 6 , x /10 = 36 /10= 3

x % 10 = 3 and print 3 , 3/10 =0

Now Both If and else if is false  so function ends

Hence Output is 6 3

Q10)

Answer is Option B

Now as X<0 So If condition didn't satisfy and we go to else and as x is not equal to 0 so it is True and we print x . So -85 is printed

These are the answer for each of the question

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