# HG changeset patch
# User nishanth
# Date 1284567048 -19800
# Node ID 05a7b05061341367242fe890094f975647df9485
# Parent  bc023595e167fa00541a45d13df81f6b22e608b0
initial commit for input_output

diff -r bc023595e167 -r 05a7b0506134 input_output.rst
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/input_output.rst	Wed Sep 15 21:40:48 2010 +0530
@@ -0,0 +1,182 @@
+Hello friends and welcome to the tutorial on Input/Output
+
+{{{ Show the slide containing title }}}
+
+{{{ Show the slide containing the outline slide }}}
+
+Input and Output are used in almost every program we use.
+In this tutorial, we shall learn
+
+ * Outputting data
+ * Taking input from the user
+
+type
+::
+ 
+    a = "This is a string"
+    a
+    print a
+     
+print a prints the value of a which is obvious.
+As you can see, even when you type just a, the value of a is shown.
+But there is a difference.
+
+Typing a shows the value of a while print a prints the string. This difference
+becomes more evident when we use strings with newlines in them.
+type
+::
+
+    b = "A line \n New line"
+    b
+    print b
+
+As you can see, just typing b shows that b contains a newline character.
+While typing print b prints the string and hence the newline.
+
+Moreover when we type just a, the value a is shown only in interactive mode and
+does not have any effect on the program while running it as a script.
+
+We shall look at different ways of outputting the data.
+
+print statement also accepts the syntax of C's printf statement.
+Various arguments can be passed to print using modifiers.
+type
+::
+
+    x = 1.5
+    y = 2
+    z = "zed"
+    print "x is %2.1f y is %d z is %s"%(x,y)
+
+As you can see, the values of x and y are substituted in place of %2.1f and %d
+
+{{{ Pause here and try out the following exercises }}}
+
+%% 1 %% What happens when you do print "x is %d y is %f"%(x)
+
+{{{ continue from paused state }}}
+
+We see that the int value of x and float value of y are printed corresponding
+to the modifiers used in the print statement.
+
+We can also see that print statement prints a new line character at the end of
+line, everytime it is called. This can be suppressed by using a "," at the end
+print statement.
+
+Let us see this by typing out following code on an editor as print_example.py
+
+{{{ open an editor }}}
+type
+::
+
+    print "Hello"
+    print "World"
+
+    print "Hello",
+    print "World"
+
+Now we run the script using %run /home/fossee/print_example.py
+
+As we can see, the print statement when used with comma in the end, prints a
+space instead of a new line.
+
+Now we shall look at taking input from the user.
+We will use the ~~raw_input~~ for this.
+type
+::
+
+    ip = raw_input()
+
+The cursor is blinking indicating that it is waiting for input    
+type
+::
+
+    an input
+
+and hit enter.
+Now let us see what is the value of ip by typing.
+::
+
+    ip
+
+We can see that it contains the string "an input"
+
+{{{ Pause here and try out the following exercises }}}
+
+%% 2 %% enter the number 5.6 as input and store it in a variable called c.
+
+{{{ continue from paused state }}}
+
+We have to use the raw_input command with variable c.
+type
+::
+
+    c = raw_input()
+    5.6
+    c
+
+Now let us see the type of c.
+
+::
+
+    type(c)
+
+We see that c is a string. This implies that anything you enter as input, will
+be taken as a string no matter what you enter.
+
+{{{ Pause here and try out the following exercises }}}
+
+%% 3 %% What happens when you do not enter anything and hit enter
+
+{{{ continue from paused state }}}
+
+::
+
+    d = raw_input()
+    <RET>
+    d
+
+We see that when nothing is entered, an empty string is considered as input.
+
+raw_input also can display a prompt to assist the user.
+::
+
+    name = raw_input("Please enter your name: ")
+
+prints the string given as argument and then waits for the user input.
+
+{{{ Pause here and try out the following exercises }}}
+
+%% 4 %% How do you display a prompt and let the user enter input in a new line
+
+{{{ continue from paused state }}}
+
+The trick is to include a newline character at the end of the prompt string.
+::
+
+    ip = raw_input("Please enter a number in the next line\n> ")
+
+prints the newline character and hence the user enters input in the new line
+
+{{{ Show summary slide }}}
+
+This brings us to the end of the tutorial.
+we have learnt
+
+ * How to print some value
+ * How to print using modifiers
+ * How to take input from user
+ * How to display a prompt to the user before taking the input
+
+{{{ Show the "sponsored by FOSSEE" slide }}}
+
+#[Nishanth]: Will add this line after all of us fix on one.
+This tutorial was created as a part of FOSSEE project, NME ICT, MHRD India
+
+Hope you have enjoyed and found it useful.
+Thankyou
+ 
+.. Author              : Nishanth
+   Internal Reviewer 1 : 
+   Internal Reviewer 2 : 
+   External Reviewer   :