Part 11 - C# Tutorial - switch statement in C# Video Lecture - C sharp

so welcome to prism technologies I am
Bankard this is part 11 switch statement
in c-sharp in part 10 we have seen how
if statements work in c-sharp
so in this session we will learn switch
statement break statement and go-to
statement so when we actually use which
statement actually multiple if-else
statements can be replaced with the
switch statement if you look at this
slide on the left hand side we have
multiple if else if statements which are
actually replaced by switch statement
let's look at an example let's prompt
the user to enter a number please enter
a number and once the user has entered
the number it will go ahead and store it
in a variable called user number so we
read that number the user has entered
from the console and we need to convert
that to India and we use the int dot
parse method to do that job for us so
once you have the number that the user
has entered you can make basically make
use of switch statement let's let's
write the program using if statement if
user number equal to 10 then we can say
console dot write line
your number is 10 now similarly else if
the number is 20 then user number is 20
else if it's 30 then we print the
message your number is 30 if it's not 10
20 or 30 then we will have an else part
where we will say your number is not 10
20 and 30 something else number is not
10 20 and 30
okay now if you look at this particular
program you know it's pretty simple so
let's go ahead and run that so please
enter a number we are asking the user to
enter a number so once he enters let's
say for example 20 and press the center
it says your number is 20 ok so what's
happening here it first checks ok easier
number 10 now it comes to the elsif bar
a number is 20 yes it prints this line
and then it won't bother checking the
other conditions because this is else if
in the previous part we have seen why
okay
now this entire if else if section can
actually be replaced with this which
statement so let's see how to do that so
instead of using that multiple if-else
statements I can say switch and I want
to switch on this user number okay so
switch on the user number and now the
value in that user number can be any
integer so my case statement should
actually be an integer for example it
can be 10 so if it is 10 what is it that
you want to do I want to print a message
on to this console saying that your
number is 10 so we will say your number
is
damn and we need to have a break
statement okay all I have to do if the
number is ten is print that the number
is ten and break out of the switch
statement okay similarly if the number
is twenty and thirty if the number is
twenty then we want to print a message
saying that the number is twenty if it
is thirty then we want to print a
message saying so and if it is not ten
twenty or thirty then we can have a
default case where we can say your
number is not 10 20 and 30 your number
is not 10 20 and 30
and then obviously break go to the
switch statement so instead of multiple
elsif statements you know we are using
switch statements which in case so
what's going to happen here the number
that the user has entered you know we
get it that into this variable and if it
is 10 this piece of code gets executed
if it is 20 this piece of code and so on
and so forth and we need to have break
statement up to each case statement okay
so if it's Stan it executes this and
breaks out of the switch statement so if
I go ahead and run this program and if I
enter let's say 20 so it comes to that
piece 20 execute that line and breaks
out of the switch statement so break
statement why do we use it to break out
of the switch statement so that the rest
of piece of code are not executed
okay now let's slightly change this
program to you know to understand
another concept we can have multiple
case statements together actually I can
remove that remove that a slight
modification to this program so I'm
saying case 10 20 and 30 your number is
30 instead of hard-coding that what I
can do is I can use a place holder and
then if it is 10 20 or 30 print that
number if I didn't if it is anything
else then we say your number is not 10
20 and 30 effectively what we are doing
here is we are joining multiple case
statements together now this case
statement doesn't have any code this
case statement doesn't have any code the
only code that's present is on this case
statement so if the user number is 10 or
20 what's going to happen it comes here
there's no code to execute so it falls
to this and there's no code to execute
here as well so it it falls to this code
this case and then execute this code so
for case 10 20 or 30 the same piece of
code gets executed so it's possible to
combine case statements together like
this if you want the same piece of code
to be executed for those conditions okay
so now if I go ahead and run my program
there isn't going to be any visible
difference except that we have
structured that a little different so if
I go ahead and n to 20 your number is 20
all right so we have seen how to replace
multiple if-else statements with a
switch statement now we also have seen
how to join multiple case statements
together
and now we will understand go-to
statement actually will will create a
productive you know a simple practical
application maybe a coffee purchasing
program okay this is going to consume a
little of time so we will do that in our
next session thank you for listening
have a great day