ASP.NET PDF Viewer using C#, VB/NET

Throughout these examples, you have probably noticed that all the strings printed out by Python are still quoted That s because it prints out the value as it might be written in Python code, not how you would like it to look for the user If you use print, however, the result is different: >>> "Hello, world!" 'Hello, world!' >>> 10000L 10000L >>> print "Hello, world!" Hello, world! >>> print 10000L 10000 As you can see, the long integer 10000L is simply the number 10000 and should be written that way when presented to the user But when you want to know what value a variable refers to, you may be interested in whether it s a normal integer or a long, for example What is actually going on here is that values are converted to strings through two different mechanisms.

winforms pdf 417 reader, winforms qr code reader, winforms upc-a reader, winforms data matrix reader, winforms gs1 128, winforms ean 13 reader, c# remove text from pdf, find and replace text in pdf using itextsharp c#, winforms code 39 reader, c# remove text from pdf,

Meaow! Woof! Meaow!

Use a chart, graph, or diagram. You can sketch a chart, graph, or diagram on a single slide or across three Explanation or Detail slides, depending on what your headlines say. The bottom-row Detail slides in Figure 7-24 feature sketches of charts to illustrate single headlines.

In this example, you define three classes: an Animal class, and Dog and Cat classes that inherit from Animal. In the code at the bottom, you create an array of various animal objects: two Cat objects and a Dog object (whose names are all processed by the generic initialize method from the Animal class). Next, you iterate over each of the animals, and on each loop you place the animal object into the local variable, animal. Last, you run puts animal.talk for each animal in

turn. As the talk method is defined on both the Cat and Dog class, but with different output, you get the correct output of two Meaow! s and two Woof! s. This demonstration shows how you can loop over and work upon objects of different classes, but get the expected results in each case if each class implements the same methods. If you were to create new classes under the Cat or Dog classes with inheritance (for example, class Labrador < Dog), then Labrador.new.talk would still return Woof! thanks to inheritance. Some of Ruby s built-in standard classes (such as Array, Hash, String, and so on) have polymorphic methods of their own. For example, you can call the to_s method on many built-in classes to return the contents of the object as a string:

7

The output isn t particularly useful in this case, but being able to rely on most objects to return a string with to_s comes in particularly useful in many situations.

You can use both mechanisms yourself, through the functions str, which simply converts a value into a string in some reasonable fashion that will probably be understood by a user, for example, and repr, which creates a string that is a representation of the value as a legal Python expression:9 >>> print repr("Hello, world!") 'Hello, world!' >>> print repr(10000L) 10000L >>> print str("Hello, world!") Hello, world! >>> print str(10000L) 10000 A synonym for repr(x) is `x` (here you use backticks, not single quotes).

In Ruby, it s possible to place classes within other classes. These are called nested classes. Nested classes are useful when a class depends on other classes, but those classes aren t necessarily useful anywhere else. They can also be useful when you want to separate classes into groups of classes rather than keep them all distinct. Here s an example:

FIGURE 7-24 Explanation slides with parts of a diagram and Detail slides with photographs, screen captures, and charts.

Nested classes are defined in the same way as usual. However, they re used differently. From within Drawing, you can access the Line and Circle classes directly, but from outside the Drawing class, you can only access Line and Circle as Drawing::Line and Drawing::Circle. For example:

class Drawing def Drawing.give_me_a_circle Circle.new end class Line end class Circle def what_am_i "This is a circle" end end end a = Drawing.give_me_a_circle puts a.what_am_i a = Drawing::Circle.new puts a.what_am_i a = Circle.new puts a.what_am_i

This can be useful when you want to print out a sentence containing a number, for example: >>> temp = 42 >>> print "The temperature is " + temp Traceback (most recent call last): File "<pyshell#61>", line 1, in print "The temperature is " + temp TypeError: cannot add type "int" to string >>> print "The temperature is " + `temp` The temperature is 42 The first print statement doesn t work because you can t add a string to a number The second one, however, works because I have converted temp to the string "42" by using the backticks..

a = Drawing.give_me_a_circle calls the give_me_a_circle class method, which returns a new instance of Drawing::Circle. Next, a = Drawing::Circle.new gets a new instance of Drawing::Circle directly, whereas it doesn t succeed because Circle doesn t exist. That s because as a nested class under Drawing, it s known as Drawing::Circle instead.