Unit-3: Arrays in Computer Science

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Questions and Answers

What is the correct formula to calculate the length of an array in C?

Length = Upper Limit + Lower Limit

Length = Upper Limit – Lower Limit + 1 (correct)

Length = Upper Limit – Lower Limit + 2

Length = Upper Limit – Lower Limit

What happens if the number of values in the initialization list exceeds the size of the array?

The excess values will cause an error during compilation.

All values will be stored and the array size will increase.

The excess values will be ignored. (correct)

The last value will overwrite the first value.

If an array is initialized with fewer values than its declared size, what happens to the remaining elements?

They will cause a runtime error.

They will contain garbage values.

They will be automatically set to zero. (correct)

They will retain their previous values.

Why might execution fail when accessing an uninitialized element of an array in C?

Array bounds are not checked at runtime in C. Signup and view all the answers

What is the result of the following declaration: float total = {24.2, -12.5, 35.1};

total will contain an array of size 5 with zeros added. Signup and view all the answers

What type of array allows storing multiple rows and columns of values?

Multi Dimensional Array Signup and view all the answers

How is a Single Dimensional Array defined in C programming?

With an array name followed by a size specification in square brackets Signup and view all the answers

Which of the following correctly describes a 1-D array?

It stores data in a linear form Signup and view all the answers

What characteristic must all elements in an array share?

They must have a common data type Signup and view all the answers

Which notation is used to access the third element of an array named 'x'?

x[2] Signup and view all the answers

What is the primary purpose of using arrays in programming?

To manage structured data collections efficiently Signup and view all the answers

What element of arrays allows for the identification of their dimensionality?

The number of subscripts used Signup and view all the answers

Which of the following correctly defines a Single Dimensional Array?

A linear arrangement of values all sharing the same data type Signup and view all the answers

What is the correct syntax for defining an array of integers named 'scores' with 5 elements?

int scores[5]; Signup and view all the answers

Which declaration will result in an array of size 6 for the character array?

char name[6]; Signup and view all the answers

What is the range of valid indices for an array with 10 elements?

0 to 9 Signup and view all the answers

Why is the declaration 'int marks[n];' illegal?

n must be a constant value. Signup and view all the answers

In memory storage, if an array starts at address x and each element uses k bytes, where will the element a[3] be located?

x + 3k Signup and view all the answers

What type of data structure does an array represent?

Homogenous data types Signup and view all the answers

Which of the following is an example of how an array named 'temperature' of 5 float values can be initialized?

float temperature[] = {30.0, 31.0, 32.0, 33.0, 34.0}; Signup and view all the answers

What happens if you try to access an array index outside its defined range?

It may retrieve a random memory value. Signup and view all the answers

Study Notes

Unit-3: Arrays

Arrays are a structured data type used to store multiple data items with common characteristics.
Mathematically, arrays are denoted using indexed form (e.g., x₁, x₂, x₃, ..., xₙ).
Arrays are essential in various applications, including reading numbers from input, sorting data, and calculating statistical measures (like mode and standard deviation).

Examples of Arrays

Real-world examples include a list of books, a table of student grades, or a set of leaves arranged in a circular pattern.
Arrays can be visualized as collections of data items arranged in a linear or multi-dimensional structure.

Basic Concept

Arrays in computer science allow storing and manipulating ordered collections of data.
Essential for multiple data items of similar characteristics.

1-D, 2-D, and 3-D Arrays

1-D array: A single row (list).
2-D array: A table (matrix - rows & columns).
3-D array: A cube-like structure (rows, columns, and depth).

Introduction to Arrays

Arrays are structured collections of homogenous data (same type).
Stored in contiguous memory locations.
The number of subscripts represents dimensions of the array (e.g., a single subscript for 1-D, two subscripts for 2-D).

Defining an Array

Array definition resembles variable declaration, but includes a size specification (e.g., integer constant representing number of elements in a 1D array).
General syntax: storage-class data-type arrayname[expression];

Defining an Array - Example

Using initialization: int marks[6] = {89, 90, 76, 78, 98, 86};
Array index starts at 0. The size of an array cannot change after definition.

Length of an Array

Length of array = Upper Limit - Lower Limit + 1
Example for int marks[8]: Length is 8; upper limit is 7, lower limit is 0

Array Bounds in C

In C, there's no automatic bound checking. Accessing an element out of array bounds can lead to program errors, not caught during the compile.

Basic Array Initialization

Initializing arrays: int marks[5] = {72, 83, 65, 80, 76};
If the supplied values are fewer than the array's allocated space, the remaining elements are set to zero for numeric types, and indeterminate for char types.

Initialization with Subscript

Elements can be explicitly initialized while declaring, i.e int matrix[4][3] = {[0][0]=1, [1][1]=5, [2][2]=9};

Accessing Array Elements

Elements are accessed using array_name[index].

How an Array is Stored in Memory

Successive array elements are stored sequentially in memory.
The starting address (x) and number of bytes per element (k) determines the memory location of any element a[i].

String Arrays

Strings are arrays of characters that end with null character \0.
Characters are stored in memory in ASCII format (e.g."Hello").
Strings are initialized within double quotes: char str[] = "hello";

String functions

strcpy: Copies the contents of one string to another
strlen: Calculates and returns the length of the string.
strcmp: Compares two strings; returns 0 if identical, non-zero otherwise
strcat: Concatenates (joins) two strings.

2-D Arrays

2-D arrays are used to store tabular data.
Arrays are declared as type arrayName[rowSize][colSize];
Example: int marks[4][5];

2-D Arrays access

Elements are accessed using two indices arrayName[row][col];

2-D Arrays Storage

Elements are stored row by row in memory.

Multi-Dimensional Arrays (Beyond 2-D)

C supports arrays of three or more dimensions.
Declared as type arrayName[size1][size2]...[sizeN];

Passing Arrays to Functions

Array names in function calls represent the starting address of the array.
When an array is passed to a function It's passed by reference, any changes made within the called function will affect original array's content.
Arrays passed by value would only pass the address to the function. Copying array contents is not done.

Enumerated Data Types

Enumerated data type declares a named set of constants (e.g.: colors = {red, blue, green}).
Values are assigned automatically, starting from 0. Can be explicitly defined.

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Description

Explore the fundamental concepts of arrays in computer science. This quiz covers 1-D, 2-D, and 3-D arrays, their structure, and real-world applications. Enhance your understanding of how arrays are used for organizing and manipulating data effectively.