## What this lecture covers

This lecture will help prepare you to write a program using C++

C++ Overview¶

C++ is a statically typed compiled object oriented programming language files are saved in .cpp must compile before exec: ie: terminal: g++

"basic" template for C++ programs¶

#include <iostream> //imports standard input/output stream library
using namespace std; //std is standard

int main() //returnformat namespacename() {...}
{
    return 0;
    /*return 0; is exit code for program
     *main code here
     */
}

Compiling C++ Source Files¶

while using terminal, use vi or nano to make .cpp files to compile use g++ your_file.cpp -o programName (-o flag is output compiled data into [string] name) to run the compiled file use ./programName

lt and # or Alt, Shift, and 3 to show line number in nano

C++ Statements¶

C++ statements must end with a semicolon

Basic Output¶

how do our programs display information or communicate with the user?

#include ,iostream. allows us to use the cout statement (c out) cout statements are used to display values and expressions on the output device, aka your terminal window cout syntax is

cout << var_name;

Strings¶

sequence of chars ex: "Hello, World"

ex: "Hello,World!\n" \ is the special escape character \n - new line \t - tab \\ - \ \" - "

Numerical Values¶

you can display constant numerical values

cout << 4 << " " << 10500 << "\n:";

output: 4 10500

numerical expressions¶

numerical expressions are expressings made up of numerical values and arithmetic operators

uses

addition            +
subtraction         -
multiplication      *
division            /
modulus             %

operators order (PEMDAS)¶

()
*/ %
+ -
left to right

ie:

cout << "123 + 345 =" << 123*345 << "\n";

output: 123 * 345 =42435

Variables¶

you can store values in memory using variables ie: int x=3;

in C++ you must declare datatype of the varibale ie:

#include <iostream>
using namespace std;
int main()
{
    int x=10;
    cout << x << "\n";
    cout << x+40 << "\n";
    return 0;
}

Basic Input¶

cin statements are used to take [input] through an input device: keyboard, file, etc cin statement syntax

cin >> variableName;

ie:

#include <iostream>
using namespace std;

int main()
{
    int age = 0;
    cout << "Please enter your age:";
    cin >> age;
    cout << "You are " << age << " Years old.";
}