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All questions of Stacks and Queues for Software Development Exam
Which data structure follows the Last-In-First-Out (LIFO) principle?- a)Stack
- b)Queue
- c)Linked List
- d)Heap
Correct answer is option 'A'. Can you explain this answer?
Which data structure follows the Last-In-First-Out (LIFO) principle?
a)
Stack
b)
Queue
c)
Linked List
d)
Heap
|
Rajat Sengupta answered |
Stack is the data structure that follows the Last-In-First-Out (LIFO) principle.
- Stack:
A stack is an abstract data type that represents a collection of elements. It follows the LIFO principle, which means that the last element added to the stack will be the first one to be removed. The operations performed on a stack are push (to add an element to the top of the stack) and pop (to remove the topmost element from the stack).
- Stack Visualization:
A stack can be visualized as a vertical stack of elements, where the topmost element is the one accessible for operations. When a new element is added, it is placed on top of the stack, and when an element is removed, the topmost element is removed.
- Example:
Consider the following example of a stack:
Initial stack: Empty
Operations:
1. Push element A
Stack: A
2. Push element B
Stack: B -> A
3. Push element C
Stack: C -> B -> A
4. Pop
Stack: B -> A
5. Push element D
Stack: D -> B -> A
6. Pop
Stack: B -> A
In the above example, the elements are added to the top of the stack using the push operation, and the topmost element is removed using the pop operation. The last element added (D) is the first one to be removed.
- Applications of Stack:
Stacks are widely used in various applications, including:
- Function call stack in programming languages
- Undo/redo functionality in text editors
- Expression evaluation and postfix conversion
- Backtracking algorithms
- Depth-first search in graphs
- Conclusion:
In conclusion, a stack is the data structure that follows the LIFO (Last-In-First-Out) principle. It is represented as a vertical stack of elements, where the last element added is the first one to be removed. Stacks are used in many applications and are an essential concept in computer science and software development.
- Stack:
A stack is an abstract data type that represents a collection of elements. It follows the LIFO principle, which means that the last element added to the stack will be the first one to be removed. The operations performed on a stack are push (to add an element to the top of the stack) and pop (to remove the topmost element from the stack).
- Stack Visualization:
A stack can be visualized as a vertical stack of elements, where the topmost element is the one accessible for operations. When a new element is added, it is placed on top of the stack, and when an element is removed, the topmost element is removed.
- Example:
Consider the following example of a stack:
Initial stack: Empty
Operations:
1. Push element A
Stack: A
2. Push element B
Stack: B -> A
3. Push element C
Stack: C -> B -> A
4. Pop
Stack: B -> A
5. Push element D
Stack: D -> B -> A
6. Pop
Stack: B -> A
In the above example, the elements are added to the top of the stack using the push operation, and the topmost element is removed using the pop operation. The last element added (D) is the first one to be removed.
- Applications of Stack:
Stacks are widely used in various applications, including:
- Function call stack in programming languages
- Undo/redo functionality in text editors
- Expression evaluation and postfix conversion
- Backtracking algorithms
- Depth-first search in graphs
- Conclusion:
In conclusion, a stack is the data structure that follows the LIFO (Last-In-First-Out) principle. It is represented as a vertical stack of elements, where the last element added is the first one to be removed. Stacks are used in many applications and are an essential concept in computer science and software development.
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What will be the output of the following code?
#include <iostream>
#include <queue>
using namespace std;int main() {
queue<int> myQueue;
myQueue.push(1);
myQueue.push(2);
myQueue.push(3);
while (!myQueue.empty()) {
cout << myQueue.front() << " ";
myQueue.pop();
}
return 0;
}- a)1 2 3
- b)3 2 1
- c)1 3 2
- d)2 1 3
Correct answer is option 'A'. Can you explain this answer?
What will be the output of the following code?
#include <iostream>
#include <queue>
using namespace std;
#include <iostream>
#include <queue>
using namespace std;
int main() {
queue<int> myQueue;
myQueue.push(1);
myQueue.push(2);
myQueue.push(3);
while (!myQueue.empty()) {
cout << myQueue.front() << " ";
myQueue.pop();
}
return 0;
}
queue<int> myQueue;
myQueue.push(1);
myQueue.push(2);
myQueue.push(3);
while (!myQueue.empty()) {
cout << myQueue.front() << " ";
myQueue.pop();
}
return 0;
}
a)
1 2 3
b)
3 2 1
c)
1 3 2
d)
2 1 3
|
Qudrat Chauhan answered |
The code pushes the elements 1, 2, and 3 onto the queue. The while loop dequeues elements from the queue and prints them until the queue becomes empty.
What will be the output of the following code?
#include <iostream>
#include <queue>
using namespace std;int main() {
queue<int> myQueue;
myQueue.push(5);
myQueue.push(10);
myQueue.push(15);
cout << myQueue.front() << endl;
myQueue.pop();
cout << myQueue.front() << endl;
return 0;
}- a)5, 10
- b)15, 10
- c)10, 15
- d)5, 15
Correct answer is option 'A'. Can you explain this answer?
What will be the output of the following code?
#include <iostream>
#include <queue>
using namespace std;
#include <iostream>
#include <queue>
using namespace std;
int main() {
queue<int> myQueue;
myQueue.push(5);
myQueue.push(10);
myQueue.push(15);
cout << myQueue.front() << endl;
myQueue.pop();
cout << myQueue.front() << endl;
return 0;
}
queue<int> myQueue;
myQueue.push(5);
myQueue.push(10);
myQueue.push(15);
cout << myQueue.front() << endl;
myQueue.pop();
cout << myQueue.front() << endl;
return 0;
}
a)
5, 10
b)
15, 10
c)
10, 15
d)
5, 15
|
Tanuja Mishra answered |
The code pushes the elements 5, 10, and 15 onto the queue. The front() function returns the value at the front of the queue, which is 5. After popping an element, the new front is 10.
What will be the output of the following code?
#include <iostream>
#include <stack>
using namespace std;int main() {
stack<int> myStack;
myStack.push(10);
myStack.push(20);
myStack.push(30);
cout << myStack.top() << endl;
myStack.pop();
cout << myStack.top() << endl;
return 0;
}- a)10, 20
- b)30, 20
- c)20, 30
- d)10, 30
Correct answer is option 'C'. Can you explain this answer?
What will be the output of the following code?
#include <iostream>
#include <stack>
using namespace std;
#include <iostream>
#include <stack>
using namespace std;
int main() {
stack<int> myStack;
myStack.push(10);
myStack.push(20);
myStack.push(30);
cout << myStack.top() << endl;
myStack.pop();
cout << myStack.top() << endl;
return 0;
}
stack<int> myStack;
myStack.push(10);
myStack.push(20);
myStack.push(30);
cout << myStack.top() << endl;
myStack.pop();
cout << myStack.top() << endl;
return 0;
}
a)
10, 20
b)
30, 20
c)
20, 30
d)
10, 30
|
|
Tanuja Mishra answered |
The code pushes the elements 10, 20, and 30 onto the stack. The top() function returns the value at the top of the stack, which is 30. After popping an element, the new top is 20.
Which of the following operations is NOT supported by a stack?- a)Push
- b)Pop
- c)Peek
- d)Enqueue
Correct answer is option 'D'. Can you explain this answer?
Which of the following operations is NOT supported by a stack?
a)
Push
b)
Pop
c)
Peek
d)
Enqueue
|
Code Nation answered |
Enqueue is an operation supported by a queue, not a stack. Enqueue adds an element to the rear end of a queue.
What is the time complexity for pushing an element onto a stack?- a)O(1)
- b)O(log n)
- c)O(n)
- d)O(n2)
Correct answer is option 'A'. Can you explain this answer?
What is the time complexity for pushing an element onto a stack?
a)
O(1)
b)
O(log n)
c)
O(n)
d)
O(n2)
|
Tom Tattle answered |
Pushing an element onto a stack takes constant time, regardless of the stack's size.
Given a stack st with elements [1, 2, 3, 4, 5], what will be the output of the following code?
#include <iostream>
#include <stack>
using namespace std;void display(stack<int>& st) {
while (!st.empty()) {
cout << st.top() << " ";
st.pop();
}
}int main() {
stack<int> st;
st.push(1);
st.push(2);
st.push(3);
display(st);
return 0;
}- a)1 2 3
- b)3 2 1
- c)Compile-time error
- d)Run-time error
Correct answer is option 'B'. Can you explain this answer?
Given a stack st with elements [1, 2, 3, 4, 5], what will be the output of the following code?
#include <iostream>
#include <stack>
using namespace std;
#include <iostream>
#include <stack>
using namespace std;
void display(stack<int>& st) {
while (!st.empty()) {
cout << st.top() << " ";
st.pop();
}
}
while (!st.empty()) {
cout << st.top() << " ";
st.pop();
}
}
int main() {
stack<int> st;
st.push(1);
st.push(2);
st.push(3);
display(st);
return 0;
}
stack<int> st;
st.push(1);
st.push(2);
st.push(3);
display(st);
return 0;
}
a)
1 2 3
b)
3 2 1
c)
Compile-time error
d)
Run-time error
|
|
Qudrat Chauhan answered |
The display() function pops elements from the stack and prints them until the stack becomes empty. The elements are printed in the reverse order of their insertion, resulting in "3 2 1".
What will be the output of the following code?
#include <iostream>
#include <stack>
using namespace std;int main() {
stack<int> myStack;
myStack.push(10);
myStack.push(20);
myStack.push(30);
myStack.pop();
cout << myStack.size() << endl;
return 0;
}- a)0
- b)1
- c)2
- d)3
Correct answer is option 'C'. Can you explain this answer?
What will be the output of the following code?
#include <iostream>
#include <stack>
using namespace std;
#include <iostream>
#include <stack>
using namespace std;
int main() {
stack<int> myStack;
myStack.push(10);
myStack.push(20);
myStack.push(30);
myStack.pop();
cout << myStack.size() << endl;
return 0;
}
stack<int> myStack;
myStack.push(10);
myStack.push(20);
myStack.push(30);
myStack.pop();
cout << myStack.size() << endl;
return 0;
}
a)
0
b)
1
c)
2
d)
3
|
|
Qudrat Chauhan answered |
The code pushes the elements 10, 20, and 30 onto the stack. After popping an element, the size() function returns the number of elements remaining in the stack, which is 2.
Given an input string s = "abcde", which of the following code snippets correctly stores the characters of the string into a stack st?
(I)
stack<char> st;
for (int i = 0; i < s.length(); i++) {
st.push(s[i]);
}
(II)
stack<char> st;
for (int i = s.length() - 1; i >= 0; i--) {
st.push(s[i]);
}(III)
stack<char> st;
for (int i = 0; i < s.length(); i++) {
st.push_back(s[i]);
}- a)I only
- b)II only
- c)I and II only
- d)II and III only
Correct answer is option 'B'. Can you explain this answer?
Given an input string s = "abcde", which of the following code snippets correctly stores the characters of the string into a stack st?
(I)
stack<char> st;
for (int i = 0; i < s.length(); i++) {
st.push(s[i]);
}
(II)
stack<char> st;
for (int i = s.length() - 1; i >= 0; i--) {
st.push(s[i]);
}
(I)
stack<char> st;
for (int i = 0; i < s.length(); i++) {
st.push(s[i]);
}
(II)
stack<char> st;
for (int i = s.length() - 1; i >= 0; i--) {
st.push(s[i]);
}
(III)
stack<char> st;
for (int i = 0; i < s.length(); i++) {
st.push_back(s[i]);
}
stack<char> st;
for (int i = 0; i < s.length(); i++) {
st.push_back(s[i]);
}
a)
I only
b)
II only
c)
I and II only
d)
II and III only
|
|
Qudrat Chauhan answered |
The code snippet II correctly stores the characters of the input string into a stack by iterating over the string in reverse order.
Given a stack st with elements [1, 2, 3, 4, 5], what will be the value of x after the following code execution?
#include <iostream>
#include <stack>
using namespace std;int main() {
stack<int> st;
st.push(1);
st.push(2);
st.push(3);
int x = st.top();
st.pop();
x += st.top();
return 0;
}- a)1
- b)2
- c)3
- d)4
Correct answer is option 'D'. Can you explain this answer?
Given a stack st with elements [1, 2, 3, 4, 5], what will be the value of x after the following code execution?
#include <iostream>
#include <stack>
using namespace std;
#include <iostream>
#include <stack>
using namespace std;
int main() {
stack<int> st;
st.push(1);
st.push(2);
st.push(3);
int x = st.top();
st.pop();
x += st.top();
return 0;
}
stack<int> st;
st.push(1);
st.push(2);
st.push(3);
int x = st.top();
st.pop();
x += st.top();
return 0;
}
a)
1
b)
2
c)
3
d)
4
|
|
Qudrat Chauhan answered |
The code stores the value at the top of the stack (3) in variable x. Then, it pops an element from the stack and adds its value (2) to x. Therefore, x becomes 3 + 2 = 5.
Which of the following is an example of a stack implementation?- a)Depth-First Search (DFS)
- b)Breadth-First Search (BFS)
- c)Dijkstra's Algorithm
- d)Prim's Algorithm
Correct answer is option 'A'. Can you explain this answer?
Which of the following is an example of a stack implementation?
a)
Depth-First Search (DFS)
b)
Breadth-First Search (BFS)
c)
Dijkstra's Algorithm
d)
Prim's Algorithm
|
|
Code Nation answered |
Depth-First Search (DFS) is an example of a graph traversal algorithm that uses a stack to keep track of vertices.
Given a queue q with elements [1, 2, 3, 4, 5], what will be the output of the following code?
#include <iostream>
#include <queue>
using namespace std;void display(queue<int>& q) {
while (!q.empty()) {
cout << q.front() << " ";
q.pop();
}
}int main() {
queue<int> q;
q.push(1);
q.push(2);
q.push(3);
display(q);
return 0;
}- a)1 2 3
- b)3 2 1
- c)Compile-time error
- d)Run-time error
Correct answer is option 'A'. Can you explain this answer?
Given a queue q with elements [1, 2, 3, 4, 5], what will be the output of the following code?
#include <iostream>
#include <queue>
using namespace std;
#include <iostream>
#include <queue>
using namespace std;
void display(queue<int>& q) {
while (!q.empty()) {
cout << q.front() << " ";
q.pop();
}
}
while (!q.empty()) {
cout << q.front() << " ";
q.pop();
}
}
int main() {
queue<int> q;
q.push(1);
q.push(2);
q.push(3);
display(q);
return 0;
}
queue<int> q;
q.push(1);
q.push(2);
q.push(3);
display(q);
return 0;
}
a)
1 2 3
b)
3 2 1
c)
Compile-time error
d)
Run-time error
|
|
Qudrat Chauhan answered |
The display() function dequeues elements from the queue and prints them until the queue becomes empty. The elements are printed in the order of their insertion, resulting in "1 2 3".
Given an input string s = "abcde", which of the following code snippets correctly stores the characters of the string into a queue q?
(I)
queue<char> q;
for (int i = 0; i < s.length(); i++) {
q.push(s[i]);
}
(II)
queue<char> q;
for (int i = s.length() - 1; i >= 0; i--) {
q.push(s[i]);
}
(III)
queue<char> q;
for (int i = 0; i < s.length(); i++) {
q.push_back(s[i]);
}- a)I only
- b)II only
- c)I and II only
- d)II and III only
Correct answer is option 'A'. Can you explain this answer?
Given an input string s = "abcde", which of the following code snippets correctly stores the characters of the string into a queue q?
(I)
queue<char> q;
for (int i = 0; i < s.length(); i++) {
q.push(s[i]);
}
(II)
queue<char> q;
for (int i = s.length() - 1; i >= 0; i--) {
q.push(s[i]);
}
(III)
queue<char> q;
for (int i = 0; i < s.length(); i++) {
q.push_back(s[i]);
}
(I)
queue<char> q;
for (int i = 0; i < s.length(); i++) {
q.push(s[i]);
}
(II)
queue<char> q;
for (int i = s.length() - 1; i >= 0; i--) {
q.push(s[i]);
}
(III)
queue<char> q;
for (int i = 0; i < s.length(); i++) {
q.push_back(s[i]);
}
a)
I only
b)
II only
c)
I and II only
d)
II and III only
|
|
Qudrat Chauhan answered |
The code snippet I correctly stores the characters of the input string into a queue by iterating over the string in the normal order.
What will be the output of the following code?
#include <iostream>
#include <stack>
using namespace std;int main() {
stack<int> myStack;
myStack.push(1);
myStack.push(2);
myStack.push(3);
while (!myStack.empty()) {
cout << myStack.top() << " ";
myStack.pop();
}
return 0;
}- a)1 2 3
- b)3 2 1
- c)3 1 2
- d)2 3 1
Correct answer is option 'B'. Can you explain this answer?
What will be the output of the following code?
#include <iostream>
#include <stack>
using namespace std;
#include <iostream>
#include <stack>
using namespace std;
int main() {
stack<int> myStack;
myStack.push(1);
myStack.push(2);
myStack.push(3);
while (!myStack.empty()) {
cout << myStack.top() << " ";
myStack.pop();
}
return 0;
}
stack<int> myStack;
myStack.push(1);
myStack.push(2);
myStack.push(3);
while (!myStack.empty()) {
cout << myStack.top() << " ";
myStack.pop();
}
return 0;
}
a)
1 2 3
b)
3 2 1
c)
3 1 2
d)
2 3 1
|
|
Qudrat Chauhan answered |
The code pushes the elements 1, 2, and 3 onto the stack. The while loop pops elements from the stack and prints them until the stack becomes empty.
Which data structure follows the First-In-First-Out (FIFO) principle?- a)Stack
- b)Queue
- c)Linked List
- d)Heap
Correct answer is option 'B'. Can you explain this answer?
Which data structure follows the First-In-First-Out (FIFO) principle?
a)
Stack
b)
Queue
c)
Linked List
d)
Heap
|
|
Tom Tattle answered |
Queues follow the First-In-First-Out (FIFO) principle, where the first element added is the first one to be removed.
Chapter doubts & questions for Stacks and Queues - DSA in C++ 2024 is part of Software Development exam preparation. The chapters have been prepared according to the Software Development exam syllabus. The Chapter doubts & questions, notes, tests & MCQs are made for Software Development 2024 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests here.
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