Comments

• Describe operation of code for other coders

• Ignored by compiler

/*

This is a multi-line comment

because it can go over multiple lines

*/

//This is a single line comment

Header

• Tells C++ to open a specific header for use in the program

• Headers are collections of functions that can be used in the program

• Common one in command line programming is "iostream" which allows you to use the cin and cout commands that print information to the command line.

• The namespace defines a certain set of headers to chose from.

#include <header name>

using namespace std;

Main()

• Main() is always the first function to be run, and generally when Main ends, the program ends.

• Entire function should be enclosed in { } brackets.

int main() {

Output

• Information is "printed" on the screen so that the user can read it.

• "Cout" command displays the information in a terminal application.

• "<<" is the output operator, it always follows an output command.

• Multiple outputs can be separated by output operators

• "\n" will print a new line

cout << "Some message";

cout << "Some message and..." << variable

Code: Hello World

Return

• Returns a value for a function

• When 0 is returned for main(), the program ends

Return 0;

Declaring Variables

• Defines a variable and its properties

• Multiple declarations can be separated by commas

• Cannot have the same name as a C++ keyword

• Must always start with a letter (no numbers)

• May include an underscore

• Names are case sensitive

int varName;

• This code defines varName as an interger

Operators with Variables

• Operators are symbols used to manipulate variables

• Perform mathematical operations

Input

• Allows user to input data to the program and store it in a variable

• Input operator is ">>"

• "Cin" command prompts for and stores data on in a command line application

cin >> variable;

Code: Working with Varibles

If/Then Statements

• Executes code only if a statement is true

if (condition = true) statement;

• Conditional operators are used to define conditions

Code: If/Then Statements

The For Loop

• Loops through a block of code until a condition is met

for (x=0; x>=5; x++) {

• The above code defines x as 0, says that it should run until x is greater than or equal to 5, and it should add 1 to x each time the loop runs.

• The ++ operator will add 1 to a variable

• The -- operator will subtract 1 from a variable

Code: Absolute Value

Declaring Functions

• A function can return a value and be used in expressions

• Many functions are included with C++ compiler

  • Called library functions