String and Rational Numbers ADT Quiz

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Questions and Answers

What does the StringLength operator return?

Length of the string in bytes

Boolean value indicating if the string is empty

A new string with the same length

Total number of characters in the string (correct)

What is the primary function of the StringConcat operator?

Copies one string to another

Compares two strings for equality

Calculates the length of a string

Joins two strings together (correct)

What does the StringCompare operator return when the two strings are equal?

True (correct)

False

1 (correct)

Which of the following is a precondition for the makerational operator?

The second integer must not be zero Signup and view all the answers

What is the expected result of the add operator for rational numbers?

The sum of the two rational numbers Signup and view all the answers

What does the symbol '←' represent in pseudo-code?

Assignment Signup and view all the answers

Which of the following is NOT a type of programming construct mentioned?

Do-while loop Signup and view all the answers

In the context of algorithms, what is a primitive operation?

A low-level operation identifiable in pseudo-code Signup and view all the answers

What is the output format of a sorting algorithm as described?

A sequence of numbers in ascending order Signup and view all the answers

Which factor does NOT influence the running time of an algorithm?

Programming language choice Signup and view all the answers

What characterizes a good algorithm?

Its efficiency in running time and space used Signup and view all the answers

What is one limitation of experimental studies when measuring running time?

They may not reflect the running time on untested inputs Signup and view all the answers

How can one effectively measure the running time of an algorithm?

By implementing the algorithm and using clock() for measurement Signup and view all the answers

What is a unique feature of the approach developed beyond experimental studies?

It analyzes algorithms using a high-level description Signup and view all the answers

What does a pseudo-code represent in algorithm description?

A combination of natural language and programming concepts Signup and view all the answers

Which input factor does efficiency of an algorithm correlate to?

The size of the data elements or input number bits Signup and view all the answers

What is suggested by the existence of infinitely many correct algorithms for the same problem?

There are various approaches to the same problem Signup and view all the answers

Why is it important to compare algorithms under the same conditions?

To eliminate biases introduced by different environments Signup and view all the answers

Which of the following is NOT an application of stacks?

Sorting elements in ascending order Signup and view all the answers

What is the main purpose of backtracking in algorithms?

To explore all possible solutions and eliminate invalid ones Signup and view all the answers

How does stack usage facilitate finding the correct path in a maze?

By allowing backward traversal to previous points Signup and view all the answers

Which problem is NOT typically solved using backtracking?

Tower of Hanoi Signup and view all the answers

What is the primary purpose of the realloc() function?

To resize a previously allocated memory block. Signup and view all the answers

In the context of stacks, what does 'popping' refer to?

Removing the last added element from the stack Signup and view all the answers

Which condition would necessitate the use of realloc()?

Previous memory allocation is too small for current needs. Signup and view all the answers

Which of the following scenarios would best utilize a stack data structure?

Performing depth-first traversal of a graph Signup and view all the answers

What type of value does the realloc() function return upon a successful operation?

A pointer to the resized memory block. Signup and view all the answers

Which data structure is primarily used for the redo-undo feature in applications?

Stack Signup and view all the answers

What will happen if realloc() fails to allocate the requested memory?

It returns a null pointer but keeps the old block unchanged. Signup and view all the answers

What characteristic makes backtracking suitable for solving mazes?

It allows revisiting previous states effectively Signup and view all the answers

Which of the following statements correctly describes dynamic data structures?

They can grow or shrink in size during runtime. Signup and view all the answers

In a C program, how is memory allocated for a character array using malloc()?

char *arr = (char *) malloc(sizeof(char) * 20); Signup and view all the answers

What action should be taken after a successful memory allocation with malloc()?

Check if the pointer is null. Signup and view all the answers

Which of the following does not represent an advantage of dynamic data structures?

Ability to allocate memory at compile time. Signup and view all the answers

Study Notes

String ADT

StringLength Function: Takes a string as input and returns the number of characters in the string.
StringConcat Function: Takes two strings as input and concatenates them, returning a new string with characters from the first string followed by characters from the second string.
StringCompare Function: Takes two strings as input and returns 'True' if they are equal and 'False' otherwise, indicating whether the strings are the same.
StringCopy Function: Takes two strings as input and copies all characters from the second string into the first string, overwriting its content.

Rational Numbers ADT

Definition: Represents a rational number as the quotient of two integers.
Operations: Provides operations to compare, multiply and add rational numbers.
Value Definition: A rational number is defined as RATIONALType and it must not be equal to 0.

Rational Number Operator Definition

makerational Function: Takes two integers (a and b) as input, ensuring that b is not 0. It creates and returns a rational number object represented by the quotient a/b.
Add Function: Takes two rational numbers (a and b) as input and returns a new rational number object representing the sum of the two input rational numbers, calculated as (ab+ba)/(a*b).

Algorithm Design

Definition: Specifies the step-by-step instructions to solve a problem, taking an input instance and producing the required output.
Multiple Correct Algorithms: A single problem can have various algorithms, ensuring the desired output.

Evaluating Algorithms

Good algorithm characteristics:
- Efficiency: Considers both the running time and the space used by the algorithm.
- Input Size Dependency: Its efficiency is measured in relation to the size of the input data.

Measuring Running Time

Method: Involves implementing the algorithm, running it with different input sizes and compositions, and measuring the time taken using functions like clock() to get an accurate execution time.
Limitations of Experimental Studies: It requires implementation and testing, is limited to a specific set of inputs, and demands identical hardware and software environments for comparing different algorithms.

Pseudo-Code

Description: A mixture of natural language and high-level programming constructs that represents the main ideas of an algorithm implementation.
Components:
- Expressions: Uses mathematical symbols for numeric and boolean expressions, along with assignment (←) for assignment and equality (=) for comparison.
- Method Declarations: Defined as Algorithm name(param1, param2).
- Programming Constructs: Includes decision structures (if-then-else), while-loops, repeat-loops, for-loops, and array indexing.
- Methods: Involves calls to methods like object method(args) and returns return value.

Sorting Algorithm Analysis

Requirements:
- Correctness: Ensures that for any given input, the algorithm halts with a sorted output where b1 < b2 < b3 ...
- Running Time: Dependent on the number of elements in the input sequence and the level of initial sortedness.

realloc() Function

Purpose: Resizes an existing memory block allocated previously using malloc.
Situations: Used when the allocated memory is insufficient or too generous for the current application.
Syntax: ptr_var = realloc(ptr_var, new_size); where ptr_var is the pointer to the starting address of the memory block and new_size is the desired size.

malloc() Function Example

Code Illustration: Demonstrates the usage of malloc and realloc for dynamic memory allocation.
Steps:
- Allocates 20 characters of memory using malloc.
- Copies "ABCD" string into the allocated memory.
- Uses realloc to resize the memory to 100 characters.
- Copies "space is extended upto 100 characters" into the resized memory.
- Finally, frees the allocated memory using free.

Advantages of Dynamic Data Structures

Efficient Memory Utilization: Dynamic structures only allocate memory when needed and free it when not in use.
Adaptability: Allows resizing at runtime to adjust for varying data sizes.

Application of Stacks

Expression Evaluation and Syntax Parsing: Processing expressions and parsing syntax.
Balancing of Symbols: Checking for balanced parentheses, brackets, and braces.
Infix to Postfix/Prefix Conversion: Converting expressions between different notations.
Reverse a String: Reversing the order of characters in a string.
Redo-Undo Features: Implementing features like undo/redo in editors and other applications.
Forward/Backward Navigation: Using stacks for navigation history in web browsers.
Algorithmic Applications: Employed in diverse algorithms like Tower of Hanoi, tree traversals, stock span problem, and histogram problem.

Backtracking

Definition: A recursive technique that incrementally builds solutions to problems by adding one piece at a time and discarding incorrect solutions.
Example: Finding the correct path in a maze, Knight's Tour problem, Rat in a Maze, N-Queens problem, and Sudoku Solver.

Backtracking and Maze Problem

Illustration: Describes how stacks can be used to track and revert back from incorrect paths in a maze, enabling exploration of alternate paths.
Stack Usage: Push each reached point onto the stack to remember the route taken. When encountering a wrong path, pop the stack to backtrack to the previous point.

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Description

Test your knowledge on the Abstract Data Types (ADTs) related to strings and rational numbers. This quiz covers essential functions such as string length, concatenation, comparison, and the definition and operations of rational numbers. Challenge yourself with questions designed to reinforce your understanding of these concepts.