Basic Input/Output and String Processing PDF

Computer programming I Basic Input/Output and String Processing Computer programming I Learning objectives At the end of this lesson, you should be able to Describe the concept of input and output in Java and demonstrate basic input/output operations. Explain the significance of...

Computer programming I Basic Input/Output and String Processing Computer programming I Learning objectives At the end of this lesson, you should be able to Describe the concept of input and output in Java and demonstrate basic input/output operations. Explain the significance of strings as a fundamental data type in Java. Explain the properties of Java strings and demonstrate various string methods for manipulation and analysis. Computer programming I Introduction Input/Output (I/O) operations are essential for interacting with users and processing data in Java programs. Java provides libraries and classes to perform basic input and output tasks. Computer programming I Output Operations with System.out System.out is an object of the PrintStream class used for standard output. System.out.print() and System.out.println() are used to display text on the console. Example Computer programming I Formatting Output with printf System.out.printf() allows formaed output using format specifiers like %d (integer), %f (float), %s (string), etc. Example Computer programming I Input Operations with Scanner Class The Scanner class is used to read input from the user. Methods like nextInt(), nextDouble(), and nextLine() read dierent data types. Example Computer programming I Input Operations with Scanner Class Example: Calculating Circle Area Using Scanner Computer programming I Exception Handling with try-catch for Input Scanner methods can throw exceptions if input is not of the expected type. try-catch blocks are used to handle these exceptions gracefully. Example Computer programming I Java String and Java String Methods Strings are fundamental data types in Java used to represent sequences of characters. They are widely used for text processing, manipulation, and storage. Java provides a wide range of built-in methods to manipulate and analyze strings. These methods oer powerful tools for tasks like modification, comparison, searching, and more. Computer programming I Creating Strings Strings can be created using the String class. Examples Computer programming I String Concatenation Strings can be concatenated using the + operator. Example Computer programming I String Literal vs. Object Creation Strings created using string literals are stored in the string pool. Strings created using new are stored in the heap memory. Example  Computer programming I String Immutability Strings are immutable, meaning they cannot be changed once created. Operations on strings create new strings rather than modifying the original. Example Computer programming I Mid-lesson question 1. Write a Java program that simulates a simple username and password authentication system. The program should prompt the user to enter a username and password. If the username is “mivastudent" and the password is “student345", the program should display a welcome message. Otherwise, it should display an error message. Computer programming I Answer :Mid-lesson question Computer programming I String Equality Use the equals() method to compare the content of two strings. Example: Computer programming I String Length The length() method returns the number of characters in a string. Example Computer programming I String Indexing Just like arrays, strings are zero-indexed, meaning the first character is at index 0. Individual characters can be accessed using the charAt() method. Example Computer programming I Substrings Substrings can be extracted using the substring() method. Example: Computer programming I String Comparison Use the compareTo() method to compare strings lexicographically. Example: Computer programming I More string methods concat(string): Concatenates two strings. Example: toUpperCase() and toLowerCase(): Converts the string’s case. Example: Computer programming I More string methods trim(): Removes leading and trailing whitespace. Example: indexOf(string): Returns the index of the first occurrence of the specified substring. Example: Computer programming I More string methods lastIndexOf(string): Returns the index of the last occurrence of the specified substring. Example startsWith(prefix) and endsWith(suffix): Checks if the string starts or ends with the specified prefix or suffix. Example Computer programming I Example: Reversing a String Computer programming I Example: String Manipulation and Analysis Computer programming I Example: String Manipulation and Analysis Computer programming I Summary Computer programming I Summary Basic input/output operations are fundamental for user interaction and data processing in Java programs. System.out handles standard output, while Scanner class facilitates input reading. Proper handling of input exceptions is crucial for robust program execution. Java strings are crucial for text processing, manipulation, and storage. Computer programming I Summary Java strings have properties like immutability, length, and various methods for manipulation. Java provides a rich set of string methods for manipulation and analysis. These string methods enhance eiciency and functionality when working with strings. Understanding and using string methods is crucial for eective text processing. Computer programming I FURTHER READING RESOURCES Sierra, K., & Bates, B. (2005). Head First Java: A Brain-Friendly Guide. " O'Reilly Media, Inc.". Horstmann, C. S. (2000). Core JAVA Vol Fundamentals. Burd, B. (2017). Beginning programming with Java for Dummies. John Wiley & Sons. Eckel, B. (2003). Thinking in JAVA. Prentice Hall Professional. Cosmina, I. (2018). Java for Absolute Beginners: Learn to Program the Fundamentals the Java 9+ Way. Apress. Schildt, H. (2003). Java™ 2: A Beginner’s Guide Computer programming I Thank You