C++ Basic Tutorial

1. Basic Features

• Compiled Language
  
• Case sensitive
  
• Very close to the hardware (low level language)

1.1 Basic C++ Program structure

//This is a comment
#include <iostream>

int main()
{
  std::cout << "Hello World!\n";
  return 0;
}

• Statements must end with semicolons
  
• // is a commented line
• all the main code must be within int main() {}

Basic Console commands

• cout stands for console out (Prints information to the console)
• system(“cls”): clears the console

1.2 Variables

The most common variable types in C++ are:

float: for decimal variables
char: for declaring a character
int: stores an integer number
bool: Logical value (true or false)
double: stores decimal values (larger than float and uses more memory)

Every variable must be declared in the program:

#include <iostream>
using namespace std;

int main()
{
  float myfloat;
  char mychar = 'A';
  int anyNumber = 4;
  bool olderThan18 = true;
  
  
  myfloat = 55.44;
  cout << "the number is " << myfloat;
  return 0;
}

1.3 Conditionals

• if ()
  
• else ()
  
• else if ()
  
• Ternary conditional (Short for if else) : (a == b)? cout << “true”: cout << “false”
• Switch operator: switch(variable){case consition: action; break}

Small Program 1: Body Mass Index Calculator

#include <iostream>
using namespace std;

int main()
{
    float weight;
    float height;
    float BMI;

    cout << "Type your Weight (Kg): " << endl;
    cin >> weight;
    cout << "Type your Height (m): " << endl;
    cin >> height;

    BMI = weight / (height * height);
    cout << "Your BMI is: " << BMI << endl;

    if (BMI < 18.5)
      cout << "You are underweight" << endl;
    else if (BMI > 18.5 && BMI < 25)
      cout << "Your BMI is normal" << endl;
    else
      cout << "You are overweight" << endl;
    return 0;
}

Small Program 2: Building a simple calculator

#include <iostream>
using namespace std;
int main()
{
    float num1;
    float num2;
    char operation;

    cout << "Type your operation: " << endl;
    cin >> num1 >> operation >> num2;

    switch (operation)
    {
        case '-': cout << num1 << operation << num2 << "=" << num1 - num2; break;
        case '+': cout << num1 << operation << num2 << "=" << num1 + num2; break;
        case '*': cout << num1 << operation << num2 << "=" << num1 * num2; break;
        case '/': cout << num1 << operation << num2 << "=" << num1 / num2; break;
        case '%':
        bool isNum1Int, isNum2Int;
        isNum1Int = int(num1) == num1;
        isNum2Int = int(num2) == num2;
        if (isNum1Int && isNum2Int)
            cout << num1 << operation << num2 << "=" << (int)num1 % (int)num2;
        else
            cout << "Not valid operation" << endl;
        break;
    default:cout << "Not valid operation" << endl;
    }
    return 0;
}