Variables
Programs that only output preprogrammed messages are not very useful. Ideally a program should be able to take input from a user, compute something useful from the input, and output the results for the user.
In order to accomplish this we need a method to store and process information. This information is stored in variables.
#include <iostream>
using namespace std;
int main()
{
// declaring integer variables
int x, y, z;
// setting x = 5, y = 6, and then multiplying x and y and storing the value in z
x = 5;
y = 6;
z = x*y;
// outputing z to the command prompt
cout << z << endl;
return 0;
}

Types of Variables
In C and C++ each variable must be explicitly declared. In this example you are multiplying two integers, stored in x and y, and storing the result in z.
Take a look at this cplusplus page about
types of variables as well as asciitable.com about the ASCII table, a table of integer values that represent characters. cplusplus has
good information, though their introductory information may be a bit daunting for someone new to programming.
In addition to multiplication C++ supports the following basic arthmetic operators:
Symbol  Operation 
+  Addition 
  Subtraction 
*  Multiplication 
/  Division 
%  Modulus 
The order of operations is obeyed:
Symbol(s)  Operation(s)  Order 
( )  Parentheses  1st 
*, /, or %  Multiplication, division, or Modulus  2nd 
+ or   Addition or subtraction  3rd 
For a deeper understanding, write a program to add 1 to 3.5 and then multiply by 2. Hint: you will need to use floating point numbers and parentheses.
