In this section, we will cover the fundamental concepts of variables and data types in Ada. Understanding these concepts is crucial as they form the building blocks for any program you write.

1. Variables: Named storage locations in memory that hold data.
2. Data Types: Define the type of data a variable can hold, such as integers, floating-point numbers, characters, etc.
3. Declaration: The process of defining a variable and its data type.
4. Initialization: Assigning an initial value to a variable at the time of declaration.

In Ada, variables must be declared before they are used. The general syntax for declaring a variable is:

Optionally, you can initialize a variable at the time of declaration:

• age is declared as an Integer but not initialized.
• height is declared as a Float and initialized to 5.9.
• initial is declared as a Character and initialized to 'A'.

Ada supports several built-in data types. Here are some of the most commonly used ones:

• Integer: A general-purpose integer type.
• Long_Integer: A larger integer type for bigger numbers.

• Float: A single-precision floating-point type.
• Long_Float: A double-precision floating-point type.

• Character: A single character.
• String: A sequence of characters.

• Boolean: Represents True or False.

• count is an Integer initialized to 10.
• large_number is a Long_Integer initialized to 1000000.
• temperature is a Float initialized to 36.6.
• precise_value is a Long_Float initialized to 3.141592653589793.
• letter is a Character initialized to 'B'.
• greeting is a String initialized to "Hello, Ada!".
• is_valid is a Boolean initialized to True.

Task: Declare and initialize the following variables:

1. An integer variable named score with an initial value of 95.
2. A floating-point variable named average with an initial value of 82.5.
3. A character variable named grade with an initial value of 'A'.
4. A boolean variable named passed with an initial value of True.

Solution:

Task: Write a small Ada program that declares variables of different data types, assigns values to them, and prints them to the console.

Solution:

• Ada.Text_IO is a package that provides basic input/output operations.
• Put_Line is used to print text to the console.
• Integer'Image, Float'Image, and Boolean'Image are attributes that convert the respective types to strings for printing.

• Uninitialized Variables: Always initialize variables to avoid undefined behavior.
• Type Mismatch: Ensure that the value assigned to a variable matches its declared data type.
• String Length: When declaring strings, be mindful of their length to avoid truncation or overflow.

In this section, we covered the basics of variables and data types in Ada. You learned how to declare and initialize variables, the different built-in data types, and how to use them in a program. Understanding these concepts is essential as they are the foundation for more complex programming constructs. In the next section, we will explore operators and expressions in Ada.