BPL Examples

Expressions

Boolean Expressions

var a = 5;
var b = 10;
var c = 15;
var d = true;
var e = false;
var result1 = (a < b) && (b < c);
var result2 = d && e;
var result3 = d || e;
var result4 = e || (d && false);
		

result1 is true, result2 is false, result3 is true, result4 is false.

Arithmetic Expressions

var a = 5;
var b = 10;
var c = 15;
var result1 = a + b * c;
var result2 = (a + b) * c;
var result3 = b / a + c;
		

result1 is 155 (5 + (10 * 15)), result2 is 225 ((5 + 10) * 15), result3 is 17 ((10 /5) + 15).

Variables

A form of assignment (initialization) is actually demonstrated in all the above examples.

Initialization

var x = 5;

x is 5.

Assignment

var x = 2;
var y;
y = x + 10;
x = x + y;
		

y is 12, x is 14.

Control Structures

Selection Statements

var a = 10;
var b = 15;
var max;
if(a > b)
    max = a;
else
    max = b;
        

max is 15.

Iteration

var n = 5;
var accum = 1;
while(n > 0) {
    accum = accum * n;
    n = n - 1;
}
        

accum is 120 (5 factorial).

Functions and Aggregates

var Employee =
{
    id : 1,
    newEmployee : function( first, last, age )
    {
        var nextId = id; 
        id = id + 1; 
        return { id : nextId,
                      first : first, 
                      last : last,  
                      age : age + 2,  
                      status: "good",  
                      toString : function() 
                      {  
                          return first + " " + last + " has id: " + id + 
                                 " and is " + age + " years old. This employee's" + 
                                 " status is " + status;
                      }
        };
    }
};

var one = Employee.newEmployee( "Paul", "Lorenz", 28 );
var two = Employee.newEmployee( "Bob", "Smith", 32 );

print one.toString();
print two.toString();

var e3 = Employee.newEmployee( "Paul", "Lorenz", 28 ).toString();
var e4 = Employee.newEmployee( "Bob", "Smith", 32 ).toString();

print e3;
print e4;
	
        

This will print out the following

Paul Lorenz has id: 1 and is 30 years old. This employee's status is good
Bob Smith has id: 2 and is 34 years old. This employee's status is good
Paul Lorenz has id: 3 and is 30 years old. This employee's status is good
Bob Smith has id: 4 and is 34 years old. This employee's status is good