Mastering Module 2
Data Types, Variables & Input
Video Overview
This module explores how C++ stores and processes information by mastering Data Types and Variables. You will learn how to declare memory space for different kinds of data from integers to decimals and how to make your programs interactive by capturing user input using the cin statement.
Notes
1. Simple Data Types
C++ classifies data into three main categories. Understanding these helps you manage memory efficiently.
Integral (Whole)
- int: Whole numbers (e.g.,
5000). No decimals! - bool: Logic values. Stores
true(1) orfalse(0). - char: Single character in single quotes
'A'.
'\n' is the character for a new line.
Floating-Point
- float: 4 bytes. Precision up to 7 decimals.
- double: 8 bytes. The standard for decimals (15 digit precision).
String Type
- Sequence of characters in " ".
- Requires header:
#include <string>
2. Memory Specs (Bits & Bytes)
Select a data type to inspect its memory allocation size.
Memory Allocation
00
Select Type
Waiting for input...3. Variables: The Two-Step Process
Understanding how the computer sets aside memory for your data.
The 2 Steps
- Allocation (Declaration): Instructing the computer to reserve a specific amount of memory.
- Storage (Assignment): Putting actual data into that reserved memory space.
4 Characteristics
C++ does not clean memory automatically. If you declare
int x; without giving it a value, x might contain random junk numbers!
Named Constants
Variables whose value cannot change after creation.
const double PI = 3.14;
*Must assign value immediately!
Assignment vs Initialization
At birth
int i = 10;
Later on
i = 20;
4. Input/Output Streams
Interaction in C++ uses "Streams"—a flow of data between your program and the user.
Understanding the Flow
-
cin (Console Input):
Pulls data from the keyboard into a variable. It stops reading at the first space or newline. -
cout (Console Output):
Pushes data from the program to the screen.
The Arrow Trick
The arrows point exactly where the data flows!
cout << "Enter miles: ";
// 2. Taking User Input
cin >> miles;
// 3. Cascading (Multiple inputs)
cin >> feet >> inches;
Input Buffer
Typing 10 20 stores both in a "waiting room". A single line like cin >> x >> y; grabs both at once!
What is endl?
"End Line". It moves the cursor to the next line and flushes the buffer to ensure text appears immediately.
Module 2 Knowledge Check
Answer the following multiple-choice questions to test your understanding.