Essential Programming Concepts: Variables, Data Types, and Algorithms

Variables and Constants

Variable

A named data location in a program for a value that can be changed throughout the execution of the program.

• Definition: A storage location containing data that can be modified.
• Usage: Once created and assigned, a variable can be used repeatedly and reassigned new values.
• Naming: Use descriptive names related to the stored data. Avoid spaces to prevent syntax errors.

Constant

A named data location in a program for a value that remains the same throughout the program's execution.

• Definition: A storage location for values that should not change.
• Benefit: Updating the value at the definition point automatically updates it everywhere the constant is used.

Data Types

• String: A sequence of characters or symbols.
• Numbers:
  • Integer: A whole number without decimal points (e.g., 100).
  • Real (Float): Numbers that include decimals or fractions.
• Character: A data type that holds exactly one character (e.g., 'M' or 'F').
• Boolean: A logical type that holds only two values, such as TRUE/FALSE or YES/NO.

Algorithms and Logic

Algorithm

A set of instructions designed to solve a specific problem.

Sequence

A series of instructions that must be executed in the correct order to solve a problem.

Example Sequence

1. Input the first number.
2. Store the first number.
3. Input the second number.
4. Add the first number to the second number.
5. Output the result.
6. Stop the program.

Executed

Refers to a program that is currently being run by the computer.