1. Data in a C++ Program
Numeric data and character data
Use variables to hold a data in memory
Each variable has a name
Each variable has a type
Each variable holds a value that you stored in it
Valid variable names:
salary, aug99_sales, I, AgeLimit, Amount
Never give a variable name the same name as a C++ command
Give your variables meaningful names

2. signed char (same as char) int unsigned int signed int (same as int)
Variable Types
char unsigned char
signed char (same as char) int
unsigned int signed int (same as int)
short int unsigned short int
long int long (same as long int)
signed long int (same as long) unsigned long int
float double
long double
Define Variables
main()
{ int age, weight;
char initial;
float salary;
// Rest of program follows }

3. Putting Values in Variables
main()
{ int age, dependents;
float salary;
age = 32;
salary = ;
dependents = 2;
// Rest of program follows }
{ char first, middle, last;
first = ‘G’;
middle = ‘M’;
last = ‘P’;

4. You can use a constant variable anywhere you can use a variable, but
Constant Variables
You can use a constant variable anywhere you can use a variable, but
you cannot change constant variables after their initializations at
definitions
const int days_of_week = 7;
You must put an initial value into the constant variable
C++ assumes a constant without type to be of int type
main()
{ const float salary = ;
const int age = 16;
// Rest of program follows }