Part 2 - C# Tutorial - Reading and writing to a console.avi Video Lecture

hello welcome to pledging technologies I
am blanket this is part two reading and
writing to console in part one
introduction to c-sharp we have seen
basic structure of the seizure program
what is the namespace and purpose of the
main method we have seen a very simple
c-sharp program there all this program
does if you look at this light it prints
out the message saying welcome to
pledging technologies that's what this
program does but in part two we are
going to make this program a little more
interactive for example when I run the
program it should prompt the user to
enter their name so when I run it it
last the user please enter your name the
user types in his name for example let's
say presume and you approve them should
output hello
Presi if i type my name as technologies
hello
technologies so your program should be a
little interactive it should take the
input from the user who is running the
program and then print that name back to
the console so reading from the console
and writing back to the console that's
what your program should do so in this
session as it will you will read from
the Transvaal right to the console and
there are two is basically to write to
the console One is using concatenation
and the other one is using the
placeholder syntax usually prefer
placeholders and exits because it smooth
clean now let's look at the demo okay so
what should our program do it should
print a message to the console you know
asking the user to enter their name and
in the previous example we have seen to
write a message onto the screen we can
use the right line method that is
present in the console class and we know
that console class is present inside
system namespace so console not right
line so we will ask the user to enter
their name so please enter your name so
what happens when we run this program it
will prompt the user to enter their name
so once they enter their name and
process enter which
feed that name on the from the console
for example if I run this program so it
will print this message please enter
your name so the user has to type their
name there and we should read that name
from the console and to do that to read
something see to write something on to
the console we use the right line method
to read something from the console we
can use the red line method so console
dot read line so what will this function
do this function will read a line that
has been typed onto the console by the
user who is interacting with your
program so if he types for example
Pragya and press ENTER this red line
method built read that word regime and
if you look at the intellisense this
function okay if you look at the
intellisense it says now here console
dot readline this is the fully qualified
name and if you look at the return type
this is the return type what is this
function doing it is returning a string
for example if the user types regime
that word is a string which will be
returned back to the program so red line
is going to give that name back to you
so you have to store that in a variable
so you can use it later for printing so
I am using a string variable called user
name so username equals console dot
readline so if I enter prejean this
method is going to read that and give it
to this variable and this weird variable
will hold that value now what do we want
to do with that we want to print it onto
the console and to do that again write
something onto the console we can use
write line method so console dot write
line but this time we want to say for
example if the user typed regime we want
to print message hello regime okay so I
can say hello okay
and that's the
string hello and space and to that I
want to concatenate whatever is present
in this variable okay so if the user has
entered pragya it's a hollow space
frigate if the user has entered
something like London hollow space in
London okay so let's go ahead and run
this program so when I run this program
look at this let's walk through the code
okay
so first this spline is printed consumer
right line please enter your name please
enter your name so I end up my name
Regine and then press enter so the
moment I press enter here what's going
to happen this piece of line this piece
of code will be executed it will read
that word protein and stores in this
variable and then what happens this line
will be you know executed okay in
username we have presume now soap regime
will be concatenated with this string
and on to the console if I press ENTER
it will say hello regime all right so
it's as simple as that
so this is reading from the console and
this line is writing to the console even
this line is written to the pencil okay
actually to write to the console there
are two different ways this one is
called concatenation because we are
concatenate in this string with this
string using a plus symbol and in
general people actually use a different
syntax and that one let's comment on
this one ctrl K ctrl C the keyboard
shortcut to comment or you can use the
symbols right here so comment and
uncomment uncomment and comment okay so
instead of concatenated string like this
in printing we can make use of the
placeholder syntax so how do we do that
control dot write line and within double
quotes
hello space and then within curly braces
zero so what's going to happen this is
treated as one string and within this
string there is a placeholder here what
should go into this placeholder whatever
you pass in right here so now what's
going to happen it's going to take this
variable and substitute in this location
when you execute the program so instead
of concatenating like this using plus
symbols you can actually use this place
first and that's which is mostly
preferred so when I go ahead and run the
program note put is definitely going to
be the same so game so hello Reggie okay
so you can either use placeholder syntax
like this or you can use concatenating
strings but usually people prefer this
okay so this is reading and writing to a
console the exact similar program that
we have seen just now and one important
thing to keep in mind is C sharp is case
sensitive programming language you want
to be mean by that the variables etc are
actually case sensitive for example if
you look at this program we have a
variable you know of type string called
username and we're using that variable
here now if by mistake instead of
capital you if I use this value like
that look at this we get a red squiggly
line indicating that there is an error
c-sharp is case sensitive so c-sharp
compiler treats this variable and this
variable differently because there is a
change in case so C sharp is sensitive
to that case changes so that's why you
know you need to keep that fact in mind
C sharp is kiss and citizen
okay so c-sharp is case-sensitive
programming language and just to make
this you know to let you know that how
better it is to use a placeholder syntax
let's say for example we want to print
the end users first name and last name
together okay first name comma space
last name so a program should ask the
user to enter your first name and we
should read that into a variable called
first name and I also want the users
last name so I should prompt the user to
enter the last name and to do that let's
make a copy of that so ask the user to
enter the last name and use variable s
so last name so we have two variables
one variable holding the first name
another variable holding the last name
and I want to print their first name
come a last name so I can say hello
comma and then maybe another placeholder
so this is the first placeholder and
this is the second place holder now we
have a variable okay so that would
should be if I enter you know the first
name is praveen and the last minutes
technologies that should be hello
Pridgen
comma technologies that's how I should
have so this string says okay hello if
you look at this string whatever is
highlighted hello
there's something here comma and
something here so what should come here
first name and what should go here last
name so we passed them in that order so
first name comma last name so now if you
go ahead and run this program first it
will ask the user to enter the first
name so I enter my first name and then
it will last use it into this last name
so we enter their last name and the
moment you press that hello regime come
geez okay so pretty simple a little
interactive program you know it's
talking to the user the users including
something we are reading that input from
the user
concatenate them together and printing
the amount so in this session we have
seen how to read from a console how to
write to a counsel and the two different
ways to trend a message onto the console
using concatenation and the BlazBlue
syntax and prefer the placeholders and X
because it's more convenient and we have
also seen that c-sharp is cool sensitive
and for more resources please refer to
our homepage prism tech comm and for
asp.net and C happen to be questions
through these additional resources
thank you have a great day