Top MCQs on Recursion Algorithm with Answers

Last Updated :
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; }
C 
#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));

  • 4

  • 8

  • 16

  • 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); }
C 
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); }

  • 13

  • 12

  • 9

  • 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); }
C 
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)); }

  • 11001

  • 10011

  • 11111

  • 00000

Discuss it

Question 4

What does the following function do? 

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

  • x + y

  • x + x*y

  • x*y

  • xy

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)); }
C 
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)); }

  • x*y

  • x+x*y

  • xy

  • yx

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; }
C 
#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);

  • 1000 2000 4000

  • 1000 2000 4000 4000 2000 1000

  • 1000 2000 4000 2000 1000

  • 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); }
C 
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); }

  • It returns 1 when n is a multiple of 3, otherwise returns 0

  • It returns 1 when n is a power of 3, otherwise returns 0

  • It returns 0 when n is a multiple of 3, otherwise returns 1

  • 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; }
C 
#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));

  • Stack Overflow

  • 3

  • 4

  • 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; }
C 
#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); 
  • 1 4 10
    2 4 8
    1 8 6
    3 4 5
    1 5 9
    2 5 7
    1 7 7
  • 3 4 5
    1 4 10
    2 4 8
    1 8 6
    1 5 9
    2 5 7
    1 7 7
  • 1 4 10
    2 4 8
    1 8 6
    3 4 5
  • 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; }
C 
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)?

  • 345

  • 12

  • 5

  • 3

Discuss it

There are 30 questions to complete.

Take a part in the ongoing discussion
We use cookies to ensure you have the best browsing experience on our website. By using our site, you acknowledge that you have read and understood our Cookie Policy & Privacy Policy