IMAD
Understanding Variables in Programming
Definition of Val
Val: A keyword used to declare a variable in programming.
Essential for defining variables; without it, you cannot declare a variable.
Syntax:
val <variable_name>.Example:
val myNum.
Variable Names
Each variable name must be unique; no two variables can share the same name within the same scope.
Variable names can be any string that follows naming conventions.
Examples:
myNum,num,number,nO.
Data Types
Importance of data types in programming.
Common data types include:
Boolean: Represents true or false.
Integer: Represents whole numbers without decimals.
Double: Represents numbers with decimals and also accepts whole numbers as inputs.
Declaring Variables
To declare a variable, use:
val <variable_name> : <data_type> = <value>.Example:
val myNum: Int = 1000.Important Note: The value assigned to a
valvariable is static; it cannot be changed once set.
Static vs. Dynamic Variables
Static: Once defined, the variable cannot change its value. For example,
val myNum: Int = 1000.Dynamic variables can change; they are not declared with
val.
Understanding Data Types: Int and Double
Integer (Int):
Accepts only whole numbers.
Example:
val myNum: Int = 100.
Double:
Accepts decimal values as well as whole numbers.
Example:
val myNum: Double = 100.0.Note: Using a double for variables that will never have decimal values is considered bad practice, as it indicates confusion regarding data type requirements.
Proper Coding Practices
Always choose a variable type based on the expected user input.
Example: For age, use an integer instead of a double, as age cannot be a decimal.
For lengths that can have decimal values, a double is appropriate.
Additional Data Types
Char: Represents a single character (e.g., 'a').
Syntax:
val myGrade: Char = 'A'.
String: Can hold a sequence of characters including letters, spaces, and special symbols.
Syntax:
val myName: String = "Bob".
Summary of Declaring Variables
The order of declaration is always:
val<variable_name><data_type>=followed by the assigned value.
Example of String declaration:
val myName: String = "Bob".
Key Takeaways
Understand the function of
valfor variable declaration and the importance of using correct data types based on expected data.Following good coding practices prevents errors and improves the readability and maintainability of the code.