Common Code Syntax & Data Types
While every programming language has its own unique syntax, many share fundamental concepts regarding data types and variable declaration. Understanding these commonalities makes learning new languages significantly easier.
1. Variables
A variable is a container for storing data values.
Declaration
Different languages handle variable declaration differently, often depending on whether they are statically typed (type must be known at compile time) or dynamically typed (type is determined at runtime).
- JavaScript (Dynamic):
var name = "John"; // Old way (function scoped) let age = 30; // Modern way (block scoped) const PI = 3.14; // Constant (cannot be reassigned) - Java/C++ (Static):
int score = 10; String message = "Hello"; - Python (Dynamic):
score = 10 # No keyword needed message = "Hi" - PHP (Dynamic):
$score = 10; # Variables start with $
2. Integers (int)
An Integer is a whole number without decimals. It can be positive or negative.
- Examples:
0,42,-99,1024 - Usage: Counting, array indices, loop counters.
// C Example
int count = 5;3. Floating Point Numbers (float, double)
Floating point numbers represent real numbers with fractional parts (decimals).
-
Float: Single precision (usually 32-bit). Less precise, takes less memory.
-
Double: Double precision (usually 64-bit). More precise.
-
Examples:
3.14,-0.001,2.0
// Java Example
double price = 19.99;
float tax = 0.05f;4. Strings
A String is a sequence of characters used for text.
- Syntax: Usually enclosed in double quotes
"or single quotes'.
# Python Example
greeting = "Hello World"
name = 'Alice'5. Booleans (bool)
A Boolean represents one of two values: logical true or false.
- Values:
true,false(sometimes1and0). - Usage: Conditional logic (if statements).
// TypeScript Example
let isActive: boolean = true;
let hasFinished: boolean = false;