Com Sci mod 1

Question 1

What is a stack?

Answer 1

A stack is a linear data structure in which it inserts with push and deletes with pop which are allowed only at the end, called the top of the stack.
LIFO-(last in first out)

Question 2

What does the Push operation do?

Answer 2

it inserts data at the top of the stack
the data entered immediately becomes the top of the stack

Question 3

What does the Pop operator do?

Answer 3

Deletes the last inserted element from the stack

Always deletes the top element

Question 4

What does the isEmpty operation do?

Answer 4

Returns TRUE if the stack is empty else it returns FALSE

Question 5

What does the isFull operation do?

Answer 5

Returns TRUE if the stack is full, else returns FALSE

Question 6

What is a queue?

Answer 6

A queue is a linear data structure which operates in a FIFO- (First In First Out) manner

Question 7

What does the enqueue operation do?

Answer 7

Adds data to the rear end of the queue

Question 8

What does the dequeue operation do?

Answer 8

Removes elements from the head (front) of the queue

Question 9

What is a linear search?

Answer 9

Linear searches iterates through a collection one element at a time

Question 10

What is a disadvantage for a linear search?

Answer 10

It is slow for large data sets

Question 11

What is an advantage of a linear search?

Answer 11

• Fast for searches of small to medium data sets
• Does not need to be sorted
• Useful for data structures that do not have random access (linked lists)

Question 12

What is binary search?

Answer 12

Binary search is a search algorithm that finds the position of a target value within a sorted array. Half of the array is eliminated during each “step”. if the mean is not the target value and if the mean is smaller than the target value it continues to the right until the target value is found. if the mean is larger than the target value it continues to the left until the target value is found.

Question 13

What is a selection sort?

Answer 13

search through an array and keep track of the minimum value during each iteration. At the end of each iteration, we swap values.

Question 14

What is bubble sorting?

Answer 14

pairs of adjacent numbers are compared, and the elements are swapped if they are not in order

Question 15

How does a bubble sort algorithm look like?

Answer 15

include <stdio.h></stdio.h>

int main(void)
{
int a[] = {7,1,3,9,0,2,4,5,8,6};

int length =10;
for (int i = 0; i< length; i++)
{
for (int j =0; j< (length-1); j++)
// < for ascending order and > for descending order
{
if (a[j] > a[j + 1])
{
int temp= a[j];
a[j] = a[ j + 1];
a[j + 1] = temp;
}
}
}
return 0;
}

Question 16

What does a selection sort algorithm look like?

Answer 16

include <stdio.h></stdio.h>

int main()
{
int a[] = {5, 9, 7, 6, 4, 0, 2, 3, 8, 1};
int length = 10;

for (int i = 0; i < length; i ++)
{
int min_pos = i;
for (int j = i + 1; j < length; j ++)
if (a[j] < a [min_pos]) min_pos = j;

// to make it go from largest to smallest change < to >

if (min_pos != i)
{
int temp = a[i];
a[i] = a[min_pos];
a[min_pos] = temp;
}
}
for (int i = 0; i < length; i ++)
printf(“a[%d] = %d/n”, i, a[i]);

return 0;
}

Question 17

What does a binary search algorithm look like?

Answer 17

include <stdio.h></stdio.h>

int binarySearch(int array[], int x, int low, int high) {
while (low <= high) {
int mid = low + (high - low) / 2;
if (array[mid] == x)
return mid;
if (array[mid] < x)
low = mid + 1;
else
high = mid - 1;
}
return -1;
}
int main(void) {
int array[] = {3, 4, 5, 6, 7, 8, 9};
int n = sizeof(array) / sizeof(array[0]);
int x = 4;
int result = binarySearch(array, x, 0, n - 1);
if (result == -1)
printf(“Not found”);
else
printf(“Element is found at index %d”, result);
return 0;
}

Question 18

What does a linear search algorithm look like?

Answer 18

include <stdio.h></stdio.h>

int num=0, int arr[], int key=0,c=0)
void main() {
printf(“ please answer the value you are searching for”);
scanf (“%d,& key”);
for (c=0; c<100;c++)
{
if (arr [c]==key){
printf(“found”);
}
}

Question 19

what does the push function look like?

Answer 19

int push(int data){
if(!isfull()) {
top = top + 1;
stack[top] = data;
} else {
printf(“Could not insert data, Stack is full.\n”);
}
}

Question 20

what does the pop function look like?

Answer 20

int pop(){
int data;
if(!isempty()) {
data = stack[top];
top = top - 1;
return data;
} else {
printf(“Could not retrieve data, Stack is empty.\n”);
}
}

Question 21

What does isEmpty look like?

Answer 21

int isempty(){
if(top == -1)
return 1;
else
return 0;

Question 22

What does isFull look like?

Answer 22

int isfull(){
if(top == MAXSIZE)
return 1;
else
return 0;

Question 23

What does ENQUEUE look like?

Answer 23

include<stdio.h></stdio.h>

#define SIZE 5

int front =-1
int rear =-1//queue is empty
void enqueue(int Q[SIZE],int item)
{
if (rest<SIZE-1)
{
rear++;
Q[rear] = item;
}
else{
printf(“Queue is full”);
}
if (front==-1)
{
front ++
}
}

Question 24

What does DEQUEUE look like?

Answer 24

include<stdio.h></stdio.h>

#define SIZE 5

int front =-1
int rear =-1//queue is empty
void dequeue(int Q[SIZE],int item)
{
if (front<=rear)
{
printf(“\nDeleted item is %d”, Q[front]);
front++
}
else{
printf(“Queue is empty”);
front =-1;
rear =-1;
}
}

Question 25

What are Abstract Data Types

Answer 25

A way of storing and manipulating data by the use of a data structure and a set of predefined functions to carry out the operations that manipulate it