GATE CS 2017 Set 2 — Question 43

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NAT+2 / -0MediumArrays & Strings in CC ProgrammingProgramming & Data StructuresBubble, Insertion, Selection SortSortingAlgorithmsPointers & Pointer Arithmetic

Algorithms → C Programming → Arrays & Strings in C

Last updated 5 September 2026

Question

Consider the following snippet of a C program. Assume that swap(&x, &y) exchanges the contents of x and y.int main() { int array[] = {3, 5, 1, 4, 6, 2}; int done = 0; int i; while (done == 0) { done = 1; for (i=0; i<=4; i++) { if (array[i] < array[i+1]) { swap(&array[i], &array[i+1]); done = 0; } } for (i=5; i>=1; i--) { if (array[i] > array[i-1]) { swap(&array[i], &array[i-1]); done = 0; } } } printf("%d", array[3]); } The output of the program is ________.

Correct answer 3 to 3 Solution The provided C code implements a variation of the bubble sort algorithm known as the Cocktail Shaker Sort (or bidirectional bubble sort). However, the comparison operators are set such that it sorts the array in descending order. 1. Initial array: {3, 5, 1, 4, 6, 2} 2. First pass (forward): Moves smaller elements to the right. After the first forward loop, the array becomes {5, 3, 4, 6, 2, 1} . 3. First pass (backward): Moves larger elements to the left. After the first backward loop, the array becomes {6, 5, 3, 4, 2, 1} . 4. Second pass (forward): The array becomes {6, 5, 4, 3, 2, 1} . 5. Termination: In the next iteration, no swaps occur, done remains 1, and the loop terminates. The final sorted array in descending order is {6, 5, 4, 3, 2, 1} . The value at array[3] (the 4th element) is 3. Turn this into a strength. Explore AI-powered practice and doubt support with Success Tracker.

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Correct answer 3 to 3 Solution The provided C code implements a variation of the bubble sort algorithm known as the Cocktail Shaker Sort (or bidirectional bubble sort). However, the comparison operators are set such that it sorts the array in descending order. 1. Initial array: {3, 5, 1, 4, 6, 2} 2. First pass (forward): Moves smaller elements to the right. After the first forward loop, the array becomes {5, 3, 4, 6, 2, 1} . 3. First pass (backward): Moves larger elements to the left. After the first backward loop, the array becomes {6, 5, 3, 4, 2, 1} . 4. Second pass (forward): The array becomes {6, 5, 4, 3, 2, 1} . 5. Termination: In the next iteration, no swaps occur, done remains 1, and the loop terminates. The final sorted array in descending order is {6, 5, 4, 3, 2, 1} . The value at array[3] (the 4th element) is 3.

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GATE CS 2017 Set 2 — Question 43

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