Courses
Tutorials
DSA
Data Science
Web Tech

Switch to Dark Mode

Top MCQs on Recursion Algorithm with Answers

Last Updated : Mar 19, 2024

Discuss

Comments

Question 1

Predict output of following program

C++

#include <iostream>

int fun(int n)
{
    if (n == 4)
       return n;
    else return 2 * fun(n + 1);
}

int main()
{
   std::cout << fun(2);
   return 0;
}

#include <stdio.h>

int fun(int n)
{
    if (n == 4)
       return n;
    else return 2*fun(n+1);
}


int main()
{
   printf("%d", fun(2));
   return 0;
}

Java

public class Main {
    public static int fun(int n) {
        if (n == 4)
            return n;
        else return 2 * fun(n + 1);
    }

    public static void main(String[] args) {
        System.out.println(fun(2));
    }
}

Python

def fun(n):
    if n == 4:
        return n
    else:
        return 2 * fun(n + 1)

print(fun(2))

JavaScript

function fun(n) {
    if (n === 4)
        return n;
    else return 2 * fun(n + 1);
}

console.log(fun(2));

A
4
B
8
C
16
D
Runtime Error

Discuss it

Question 2

Consider the following recursive function fun(x, y). What is the value of fun(4, 3)

C++

int fun(int x, int y) {
  if (x == 0)
    return y;
  return fun(x - 1, x + y);
}

int fun(int x, int y) 
{
  if (x == 0)
    return y;
  return fun(x - 1,  x + y);
}

Java

int fun(int x, int y) {
  if (x == 0)
    return y;
  return fun(x - 1, x + y);
}

Python

def fun(x, y):
  if x == 0:
    return y
  return fun(x - 1, x + y)

JavaScript

function fun(x, y) {
  if (x === 0)
    return y;
  return fun(x - 1, x + y);
}

A
13
B
12
C
9
D
10

Discuss it

Question 3

What does the following function print for n = 25?

C++

#include <iostream>
using namespace std;

void fun(int n) {
    if (n == 0)
        return;

    cout << n % 2;
    fun(n / 2);
}

void fun(int n)
{
  if (n == 0)
    return;

  printf("%d", n%2);
  fun(n/2);
}

Java

public class Main {
    public static void fun(int n) {
        if (n == 0)
            return;

        System.out.print(n % 2);
        fun(n / 2);
    }

    public static void main(String[] args) {
        fun(10); // Example call
    }
}

Python

def fun(n):
    if n == 0:
        return

    print(n % 2, end='')
    fun(n // 2)

JavaScript

function fun(n) {
    if (n === 0)
        return;

    process.stdout.write((n % 2).toString());
    fun(Math.floor(n / 2));
}

A
11001
B
10011
C
11111
D
00000

Discuss it

Question 4

What does the following function do?

int fun(int x, int y)
{
    if (y == 0)   return 0;
    return (x + fun(x, y-1));
}

A
x + y
B
x + x*y
C
x*y
D
x^y

Discuss it

Question 5

What does fun2() do in general?

C++

#include <iostream>

int fun(int x, int y) {
    if (y == 0) return 0;
    return (x + fun(x, y-1));
}

int fun2(int a, int b) {
    if (b == 0) return 1;
    return fun(a, fun2(a, b-1));
}

int fun(int x, int y)
{
    if (y == 0)   return 0;
    return (x + fun(x, y-1));
}

int fun2(int a, int b)
{
    if (b == 0) return 1;
    return fun(a, fun2(a, b-1));
}

Java

public class Main {
    public static int fun(int x, int y) {
        if (y == 0) return 0;
        return (x + fun(x, y - 1));
    }

    public static int fun2(int a, int b) {
        if (b == 0) return 1;
        return fun(a, fun2(a, b - 1));
    }

    public static void main(String[] args) {
        // Example usage
    }
}

Python

def fun(x, y):
    if y == 0:
        return 0
    return x + fun(x, y - 1)

def fun2(a, b):
    if b == 0:
        return 1
    return fun(a, fun2(a, b - 1))

JavaScript

function fun(x, y) {
    if (y === 0) return 0;
    return x + fun(x, y - 1);
}

function fun2(a, b) {
    if (b === 0) return 1;
    return fun(a, fun2(a, b - 1));
}

A
x*y
B
x+x*y
C
x^y
D
y^x

Discuss it

Question 6

Output of following program?

C++

#include <iostream>
using namespace std;

void print(int n) {
    if (n > 4000)
        return;
    cout << n << " ";
    print(2 * n);
    cout << n << " ";
}

int main() {
    print(1000);
    cin.get();
    return 0;
}

#include<stdio.h>
void print(int n)
{
    if (n > 4000)
        return;
    printf("%d ", n);
    print(2*n);
    printf("%d ", n);
}

int main()
{
    print(1000);
    getchar();
    return 0;
}

Java

public class Main {
    public static void print(int n) {
        if (n > 4000)
            return;
        System.out.print(n + " ");
        print(2 * n);
        System.out.print(n + " ");
    }

    public static void main(String[] args) {
        print(1000);
    }
}

Python

def print_numbers(n):
    if n > 4000:
        return
    print(n, end=' ')
    print_numbers(2 * n)
    print(n, end=' ')

print_numbers(1000)

JavaScript

function print(n) {
    if (n > 4000)
        return;
    process.stdout.write(n + ' ');
    print(2 * n);
    process.stdout.write(n + ' ');
}

print(1000);

A
1000 2000 4000
B
1000 2000 4000 4000 2000 1000
C
1000 2000 4000 2000 1000
D
1000 2000 2000 1000

Discuss it

Question 7

What does the following function do?

C++

int fun(unsigned int n) {
    if (n == 0 || n == 1)
        return n;

    if (n % 3 != 0)
        return 0;

    return fun(n / 3);
}

int fun(unsigned int n)
{
    if (n == 0 || n == 1)
        return n;

    if (n%3 != 0)
        return 0;

    return fun(n/3);
}

Java

int fun(unsigned int n) {
    if (n == 0 || n == 1)
        return n;

    if (n % 3 != 0)
        return 0;

    return fun(n / 3);
}

Python

def fun(n):
    if n == 0 or n == 1:
        return n

    if n % 3 != 0:
        return 0

    return fun(n // 3)

JavaScript

function fun(n) {
    if (n === 0 || n === 1)
        return n;

    if (n % 3 !== 0)
        return 0;

    return fun(n / 3);
}

A
It returns 1 when n is a multiple of 3, otherwise returns 0
B
It returns 1 when n is a power of 3, otherwise returns 0
C
It returns 0 when n is a multiple of 3, otherwise returns 1
D
It returns 0 when n is a power of 3, otherwise returns 1

Discuss it

Question 8

Predict the output of following program

C++

#include <iostream>
using namespace std;

int f(int n) {
    if(n <= 1)
        return 1;
    if(n % 2 == 0)
        return f(n / 2);
    return f(n / 2) + f(n / 2 + 1);
}

int main() {
    cout << f(11);
    return 0;
}

#include <stdio.h>
int f(int n)
{
    if(n <= 1)
        return 1;
    if(n%2 == 0)
        return f(n/2);
    return f(n/2) + f(n/2+1);
}


int main()
{
    printf("%d", f(11));
    return 0;
}

Java

public class Main {
    public static int f(int n) {
        if(n <= 1)
            return 1;
        if(n % 2 == 0)
            return f(n / 2);
        return f(n / 2) + f(n / 2 + 1);
    }

    public static void main(String[] args) {
        System.out.println(f(11));
    }
}

Python

def f(n):
    if n <= 1:
        return 1
    if n % 2 == 0:
        return f(n // 2)
    return f(n // 2) + f(n // 2 + 1)

print(f(11))

JavaScript

function f(n) {
    if (n <= 1)
        return 1;
    if (n % 2 === 0)
        return f(n / 2);
    return f(Math.floor(n / 2)) + f(Math.floor(n / 2) + 1);
}

console.log(f(11));

A
Stack Overflow
B
3
C
4
D
5

Discuss it

Question 9

Predict the output:

C++

#include <iostream>
using namespace std;

void crazy(int n, int a, int b)
{
    if (n <= 0)
        return;
    crazy(n - 1, a, b + n);
    cout << n << " " << a << " " << b << endl;
    crazy(n - 1, b, a + n);
}

int main()
{
    crazy(3, 4, 5);
    return 0;
}

#include <stdio.h>
void crazy(int n, int a, int b)
{
    if (n <= 0)
        return;
    crazy(n - 1, a, b + n);
    printf("%d %d %d \n",n,a,b);
    crazy(n-1, b, a+n);
}

int main()
{
    crazy(3, 4, 5);
    return 0;
}

Java

public class Crazy {
    public static void crazy(int n, int a, int b) {
        if (n <= 0)
            return;
        crazy(n - 1, a, b + n);
        System.out.println(n + " " + a + " " + b);
        crazy(n - 1, b, a + n);
    }

    public static void main(String[] args) {
        crazy(3, 4, 5);
    }
}

Python

def crazy(n, a, b):
    if n <= 0:
        return
    crazy(n - 1, a, b + n)
    print(n, a, b)
    crazy(n - 1, b, a + n)
crazy(3, 4, 5)

JavaScript

function crazy(n, a, b) {
    if (n <= 0)
        return;
    crazy(n - 1, a, b + n);
    console.log(n, a, b);
    crazy(n - 1, b, a + n);
}

crazy(3, 4, 5);

A
```
1 4 10
2 4 8
1 8 6
3 4 5
1 5 9
2 5 7
1 7 7
```
B
```
3 4 5
1 4 10
2 4 8
1 8 6
1 5 9
2 5 7
1 7 7
```
C
```
1 4 10
2 4 8
1 8 6
3 4 5
```
D
```
3 4 5
1 5 9
2 5 7
1 7 7
```

Discuss it

Question 10

Consider the following recursive C++ function that takes two arguments

C++

 unsigned int foo(unsigned int n, unsigned int r) {
  if (n  > 0) return (n%r +  foo (n/r, r ));
  else return 0;
}

unsigned int foo(unsigned int n, unsigned int r) {
    if (n > 0) return (n % r + foo(n / r, r));
    else return 0;
}

Java

public class Main {
    public static int foo(int n, int r) {
        if (n > 0) return (n % r + foo(n / r, r));
        else return 0;
    }
}

Python

def foo(n, r):
    if n > 0:
        return (n % r + foo(n // r, r))
    else:
        return 0

JavaScript

function foo(n, r) {
    if (n > 0) return (n % r + foo(Math.floor(n / r), r));
    else return 0;
}

What is the return value of the function foo when it is called foo(345, 10)?

A
345
B
12
C
5
D
3

Discuss it

Master DSA and also get 90% fee refund on completing 90% course in 90 days! Take the Three 90 Challenge today.

Step into the Three 90 Challenge – 90 days to push limits, break barriers, and become the best version of yourself! Don't miss your chance to upskill and get 90% refund. What more motivation do you need? Start the challenge right away!

Tags:

DSA Quiz

There are 30 questions to complete.

Take a part in the ongoing discussion