Practice exercise -- Allocating memory Loading data into memory: 1. Instruct computer to allocate memory 2. Invoke program statements to put data into allocated memory Constant: A memory location whose value may not be changed General form: define ('CONSTANT_NAME', constantValue); Examples: define ('NAME_PROMPT', "Enter your name"); define ('PI', 3.1416); define ('FULL_CAPACITY', 30); Variable: Memory location that may be changed $charIdentifier='a', $intIdentifier=1, ..., $stringIdentifier="hello"; Storing data: Store with an assignment statement $identifier = expression; Printing (stored) data: print ($identifier1.$identifer2...); Statement identifier value after each statement -------------------------------- ----------- ---------------------------- 1. $a; $b = 2; $a = $b; 2. $d = 2; $x = 3; $y = 4; $y + 5 = $x * 3; 3. $inches = 12.0; $inches *= 3.0; $feet = $inches / 12; 4. define('E', 5); 5. $x = -5.5; $y = 17.5; $d = 4; $y = $d - $x + $y; 6. $n; $n = 1.23; 7. $count = 0; print ($count++); print (++$count);