# Practice Questions for Recursion | Set 1

Explain the functionality of following functions.

Question 1

 `int` `fun1(``int` `x, ``int` `y)  ` `{ ` `  ``if``(x == 0) ` `    ``return` `y; ` `  ``else` `    ``return` `fun1(x - 1,  x + y); ` `} `

Answer: The function fun() calculates and returns ((1 + 2 … + x-1 + x) +y) which is x(x+1)/2 + y. For example if x is 5 and y is 2, then fun should return 15 + 2 = 17.

Question 2

 `//minimum index finder ` `int` `minIndex(``int` `arr[], ``int` `s, ``int` `e) ` `{ ` `    ``int` `sml = INT32_MAX; ` `    ``int` `mindex; ` `    ``for` `(``int` `i = s; i < e; i++) ` `    ``{ ` `        ``if` `(sml > arr[i]) ` `        ``{ ` `            ``sml = arr[i]; ` `            ``mindex = i; ` `        ``} ` `    ``} ` `    ``return` `mindex; ` `} ` ` `  `void` `fun2(``int` `arr[], ``int` `start_index, ``int` `end_index) ` `{ ` `  ``if``(start_index >= end_index)    ` `     ``return``; ` `  ``int` `min_index;  ` `  ``int` `temp;  ` ` `  `  ``/*minIndex() returns index of minimum value in  ` `    ``array arr[start_index...end_index] */` `  ``min_index = minIndex(arr, start_index, end_index); ` ` `  `  ``temp = arr[start_index]; ` `  ``arr[start_index] = arr[min_index]; ` `  ``arr[min_index] = temp;         ` ` `  `  ``fun2(arr, start_index + 1, end_index); ` `}      `

Answer: The function fun2() is a recursive implementation of Selection Sort.

Don’t stop now and take your learning to the next level. Learn all the important concepts of Data Structures and Algorithms with the help of the most trusted course: DSA Self Paced. Become industry ready at a student-friendly price.

My Personal Notes arrow_drop_up

Improved By : NikSta

Article Tags :
Practice Tags :

19

Please write to us at contribute@geeksforgeeks.org to report any issue with the above content.