Programs that only output pre-programmed 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.
Types of Variables
using namespace std;
// 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;
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:
The order of operations is obeyed:
| Symbol || Operation |
| + || Addition |
| - || Subtraction |
| * || Multiplication |
| / || Division |
| % || Modulus |
| 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.