Computer Programming - Arrays and Strings

Computer Programming - Arrays and Strings

• Arrays are collections of data items of the same type, accessed by a common name.
• Arrays hold a finite, sequential collection of homogeneous data.
• Arrays are containers holding collections of data.
• Array size is fixed before use.
• Arrays store data sequentially in memory.
• Array elements must share the same data type.

Examples of Array Usage

• Customer lists with phone numbers
• Daily rainfall tables
• Employee lists in an organization
• Student test scores

Array Structure

• Arrays have elements starting from index 0.
• The index of the last element is one less than the array size.
• The first index is known as the lower bound.
• The last index is known as the upper bound.

Declaring Arrays

• Array variables are declared like other variables, with an added pair of square brackets specifying the size.
• Syntax: type arrayName[size]; (e.g., int group[10];)

Initializing Arrays

• Static initialization: All elements' values are defined during declaration with curly braces and commas.
  • Example: int marks[5] = {90, 86, 89, 76, 91};
• Dynamic initialization: Elements are assigned values during program execution.
  • Example: scanf("%d", &arr[i]);

Advantages of Arrays

• Efficient use of memory.
• Easy access to elements using indexing.
• Simple traversal using loops.
• Relatively easy to sort.
• Uses less code than other methods.

Disadvantages of Arrays

• Insertion and deletion can be expensive due to memory reallocation needs.
• Fixed size restricts the amount of data at declaration time..
• Arrays are not dynamic, unlike linked lists.

Types of Arrays

• One-dimensional (single)
• Two-dimensional
• Multidimensional

One-Dimensional Arrays

• Elements are stored sequentially, like a row.
• Syntax: datatype array_name[size]

Accessing Array Elements

• Elements are accessed using their index, inside square brackets.
• Index starts from 0.

Matrix Operations

• Matrices store data in rows and columns.
• Basic matrix operations include addition, subtraction, and multiplication.
• Matrix multiplication is common in programs.

Matrix Initialization

• Two Methods: Direct initialization at declaration or assigning values individually.

Matrix Accessing

• Elements within a matrix can be accessed by specifying row and column indices.

Programs for Array, Matrix Operations

• Programs demonstrating various functions are present in the slides.

Strings

• Strings are sequences of characters treated as a single data item.
• Strings are enclosed in double quotes. ("...")

String Declaration

• String declaration mirrors array declaration.
• Syntax: char stringName[size];

String Initialization

• String initialization values end with '\0' (null character)—additional characters will be ignored.

Reading Strings

• The %s format specifier is used to read strings.

Assigning Values to Strings

• String variables cannot be assigned directly after declaration.

String Handling Functions

• C has various functions (e.g., strlen, strcpy, strcmp, strcat, strrev, strlwr, strupr, strstr) to manipulate strings.
• These functions are found in the string.h header file. These functions need to be included in your programs to utilize their functionality.

Example Programs and Functionalities (in code style)

• Example shows common tasks and their respective syntaxes/functions (e.g., length calculation, copying, concatenation).