Switch case and looping kim

Switch Case and
Looping

http://eglobiotraining.com

Programming

We first define the word “programming”, it is a
computer language programmers use to develop
applications, scripts, or other set of instructions for a
computer to execute.

programming is instructing a computer to do something
for you with the help of a programming language. The role
of a programming language can be described in two ways:
 Technical: It is a means for instructing a Computer to
perform Tasks
 Conceptual: It is a framework within which we organize
our ideas about things and processes.


As an individual, I have learned that programming is a
very broad because it composes many scripts, applications
and can be used to run a program that has been part of the
programming language.

A programming language should both provide means to
describe primitive data and procedures and means to
combine and abstract those into more complex ones.


The distinction between data and procedures is not that
clear cut. In many programming languages, procedures can
be passed as data (to be applied to ``real'' data) and
sometimes processed like ``ordinary'' data. Conversely
``ordinary'' data can be turned into procedures by an
evaluation mechanism.


At first, programming is confusing because you have so
much to understand about codes that will enable to run a
program. Programming has applications and program
development, the best example for this is the Internet
bowser…

Programming is a creative process done by
programmers to instruct a computer on how to do a task.
Programming languages let you use them in different ways,
e.g adding numbers, etc… or storing data on disk for later
retrieval.


You have to consider languages to run or write your
own program, most demanded language in programming is
the DEV C++ (a full-featured Integrated Development
Environment (IDE)).

C++ is one of the most used programming languages
in the world. Also known as "C with Classes".

New to programming or thinking about it? It might surprise
you to know that there are many programmers who
program just for fun and it can lead to a job.


Switch Case

Switch case statements are a substitute for long if
statements that compare a variable to several
"integral" values ("integral" values are simply values
that can be expressed as an integer, such as the value of
a char).


basic format for using switch case:

switch ( <variable> ) {
case this-value:
Code to execute if <variable> == this-value
break;
case that-value:
Code to execute if <variable> == that-value
break;
...
default:
Code to execute if <variable> does not equal the value
following any of the cases
break;
}

The value of the variable given into switch is compared to the
value following each of the cases, and when one value matches
the value of the variable, the computer continues executing the
program from that point.


The condition of a switch
statement is a value. The case says
that if it has the value of whatever
is after that case then do whatever
follows the colon.


The break is used to break out of
the case statements. An important
thing to note about the switch
statement is that the case values may
only be constant integral expressions.


Break is a keyword that breaks
out of the code block, usually
surrounded by braces, which it is in.
In this case, break prevents the
program from falling through and
executing the code in all the other
case statements.


The default case is optional, but it is
wise to include it as it handles any
unexpected cases. Switch statements
serves as a simple way to write long if
statements when the requirements are
met. Often it can be used to process
input from a user.


This shows how would you use a Switch in a Program
#include <iostream>

using namespace std;

void playgame()
{
cout << "Play game called";
}
void loadgame()
}
cout << "Load game called";
void playmultiplayer()
{
cout << "Play multiplayer game called";
}

int main()
{
int input;

cout<<"1. Play gamen";
cout<<"2. Load gamen";
cout<<"3. Play multiplayern";
cout<<"4. Exitn";
cout<<"Selection: "; cin>> input;
switch ( input ) {
case 1: // Note the colon, not a semicolon
playgame();
break;
loadgame();
break;
playmultiplayer();
break;
cout<<"Thank you for playing!n";
break;
default: // Note the colon, not a semicolon
cout<<"Error, bad input, quittingn";
break;
}
cin.get();
}

That program will compile, but cannot be run
until the undefined functions are given
bodies, but it serves as a model (albeit
simple) for processing input. If you do not
understand this then try mentally putting in if
statements for the case statements. Default
simply skips out of the switch case
construction and allows the program to
terminate naturally. If you do not like that,
then you can make a loop around the whole
thing to have it wait for valid input. You could
easily make a few small functions if you wish
to test the code.

Looping

Loops are used to repeat a block of
code. Being able to have your program
repeatedly execute a block of code is
one of the most basic but useful tasks
in programming -- many programs or
websites that produce extremely
complex output (such as a message
board) are really only executing a
single task many times.


(They may be executing a small
number of tasks, but in principle, to
produce a list of messages only
requires repeating the operation of
reading in some data and displaying
it.) Now, think about what this
means: a loop lets you write a very
simple statement to produce a
significantly greater result simply by
repetition.


One Caveat: before going further, you
should understand the concept of C++'s
true and false, because it will be
necessary when working with loops (the
conditions are the same as with if
statements).

Three types of Loops:
for, while, and do..


FOR

For ( variable initialization; condition; variable update ) {
Code to execute while the condition is true
}


The variable initialization allows you to either declare a variable
and give it a value or give a value to an already existing variable.
Second, the condition tells the program that while the conditional
expression is true the loop should continue to repeat itself. The
variable update section is the easiest way for a for loop to handle
changing of the variable. It is possible to do things like x++, x =
x + 10, or even x = random ( 5 ), and if you really wanted to, you
could call other functions that do nothing to the variable but still
have a useful effect on the code.

Notice that a semicolon separates each of these sections, that is
important. Also note that every single one of the sections may be
empty, though the semicolons still have to be there. If the
condition is empty, it is evaluated as true and the loop will
repeat until something else stops it.


Example:

#include <iostream>

using namespace std; // So the program can see cout and endl

int main()
{
// The loop goes while x < 10, and x increases by one every loop
for ( int x = 0; x < 10; x++ ) {
// Keep in mind that the loop condition checks
// the conditional statement before it loops again.
// consequently, when x equals 10 the loop breaks.
// x is updated before the condition is checked.
cout<< x <<endl;
}
cin.get();
}

This program is a very simple example of a for loop. x is
set to zero, while x is less than 10 it calls cout<< x
<<endl; and it adds 1 to x until the condition is met.
Keep in mind also that the variable is incremented after
the code in the loop is run for the first time.

WHILE
The basic structure:
While ( condition ) { Code to execute while the
condition is true } The true represents a boolean
expression which could be x == 1 or while ( x != 7
) (x does not equal 7). It can be any combination of
boolean statements that are legal. Even, (while x
==5 || v == 7) which says execute the code while
x equals five or while v equals 7. Notice that a while
loop is the same as a for loop without the
initialization and update sections. However, an
empty condition is not legal for a while loop as
it is with a for loop.


Example:

#include <iostream>

using namespace std; // So we can see cout and endl

int main()
{
int x = 0; // Don't forget to declare variables

while ( x < 10 ) { // While x is less than 10
cout<< x <<endl;
x++; // Update x so the condition can be met eventually
}
cin.get();
}

The easiest way to think of the loop is that when it reaches the
brace at the end it jumps back up to the beginning of the
loop, which checks the condition again and decides whether to
repeat the block another time, or stop and move to the next
statement after the block.


DO..WHILE

The Structure:
do {
} while ( condition ) ;


The condition is tested at the end of
the block instead of the beginning, so the
block will be executed at least once. If the
condition is true, we jump back to the
beginning of the block and execute it
again.


A do.. while loop is basically a reversed while
loop. A while loop says "Loop while the condition is
true, and execute this block of code", a do.. while
loop says "Execute this block of code, and loop while
the condition is true".


Example:

#include <iostream>


int main()
{
int x;

x = 0;
do {
// "Hello, world!" is printed at least one time
// even though the condition is false
cout<<"Hello, world!n";
} while ( x != 0 );
cin.get();
}

Keep in mind that you must include a trailing semi-colon after
the while in the above example. A common error is to forget
that a do..while loop must be terminated with a semicolon (the
other loops should not be terminated with a semicolon, adding
to the confusion). Notice that this loop will execute once,
because it automatically executes before checking the
condition.

Programs that have tested


LOOPING STATEMENT 1
#include <iostream>

int main()
{

// nSelection must be declared outside do/while loop
int nSelection;

do
{
cout << "Please make a selection: " << endl;
cout << "1) Addition" << endl;
cout << "2) Subtraction" << endl;
cout << "3) Multiplication" << endl;
cout << "4) Division" << endl;
cin >> nSelection;
} while (nSelection != 1 && nSelection != 2 &&
nSelection != 3 && nSelection != 4);

// do something with nSelection here
// such as a switch statement

return 0;
}


LOOPING STAEMENT 2
#include <iostream>
int main()
{
int nSelection;
double var1, var2;

do
{
cin >> nSelection;
}

while (nSelection != 1 && nSelection != 2 &&
nSelection != 3 && nSelection != 4);

if (nSelection == 1)
{
cout << "Please enter the first whole number ";
cin >> var1;
cout << "Please enter the second whole number ";
cin >> var2;
cout << "The result is " << (var1+var2) << endl;
}


LOOPING STATEMENT 3
{
cin >> var1;
cin >> var2;
cout << "The result is " << (var1-var2) << endl;
}
{
cin >> var1;
cin >> var2;
cout << "The result is " << (var1*var2) << endl;
}
{
cin >> var1;
cin >> var2;
cout << "The result is " << (var1/var2) << endl;
}

return 0;
}


LOOPING STATEMENT 3
#include <iostream>
int main()
{
int nSelection;
double var1, var2;
while (1)
{
do
{
cout << "5) Exit" << endl;
cin >> nSelection;
} while (nSelection != 1 && nSelection != 2 &&
nSelection != 3 && nSelection != 4 &&
nSelection != 5);

{
cin >> var1;
cin >> var2;
cout << "The result is " << (var1+var2) << endl;
}


LOOPING STATEMENT 4
else if (nSelection == 2)
{
cin >> var1;
cin >> var2;
cout << "The result is " << (var1-var2) << endl;
}
{
cin >> var1;
cin >> var2;
cout << "The result is " << (var1*var2) << endl;
}
{
cin >> var1;
cin >> var2;
cout << "The result is " << (var1/var2) << endl;
}
else
{
return 0;
}
}
}


LOOPING STATEMENT 5
#include <iostream>

using namespace std; // So the program can see cout and endl

int main()
{
// The loop goes while x < 10, and x increases by one every loop
for ( int x = 0; x < 10; x++ ) {
// Keep in mind that the loop condition checks
// the conditional statement before it loops again.
// consequently, when x equals 10 the loop breaks.
// x is updated before the condition is checked.
cout<< x <<endl;
}
cin.get();
}


LOOPING STATEMENT 6
#include <iostream>


int main()
{
int x;

x = 0;
do {
// "Hello, world!" is printed at least one time
// even though the condition is false
cout<<"Hello, world!n";
} while ( x != 0 );
cin.get();
}


LOOPING STATEMENT 7
#include <iostream>

int main ()
{
int n;
cout << "Enter the starting number > ";
cin >> n;

while (n>0) {
cout << n << ", ";
--n;
}

cout << "FIRE!n";
return 0;
}


SWITCH CASE 1

SWITCH CASE
#include <iostream>


int main ()

{

int score;

cout << "What was your score?";

cin >> score;

if (score <= 25)

{

cout << "nOuch, less than 25...!";

}


SWITCH CASE 2
else if (score <= 50)

{

cout << "nYou score aint great mate..";

}


{

cout << "nYour pretty good, wel done man!";

}


{

cout << "nYou got to the top!!!";

}


SWITCH CASE 3
else

{

cout << "nYou cant score higher than 100!!! Cheater!!!!";

}

cin.ignore();

cin.get();

return 0;

}


SWITCH CASE 4

#include <iostream>


int main(){
cout << "Enter a number between 1 and 5!" << endl;
int number;
cin >> number;
if(number == 1){
cout << "one";
}
else if(number == 2){
cout << "two";
}
cout << "three";
}
cout << "four";
}
cout << "five";
}
else{
cout << number << " is not between 1 and 5!";
}
cout << endl;
system("pause");
}

SWITCH CASE 5
#include <iostream>
int main()
{
int price_before_discount, RM, dozen, total_price;

cout<< "How much is the price before discount for 1 dozen boxes of tissue?n";
cout<<"RM ";
cin>>price_before_discount;
cout<<"nn";

cout<< "How many dozen boxes of tissue you buy?n";
cin>>dozen;
cout<<"nn";

switch (dozen)
{
total_price = ((price_before_discount*dozen) * (95/100));
case '1': cout<< "Total price is RM ";
cout<<RM;
cout<<"nn";
break;

cout<<RM;
cout<<"nn";
break;

cout<<RM;
cout<<"nn";
break;

case '4' : cout<< "Total price is RM ";
cout<<RM;
cout<<"nn";
break;

default : cout<< "Total price is RM ";
cout<<RM;
cout<<"nn";
}

return 0;
}

SWITCH CASE 6
#include <stdlib.h>
#include <stdio.h>

int main(void) {
int n;
printf("Please enter a number: ");
scanf("%d", &n);
switch (n) {
case 1: {
printf("n is equal to 1!n");
break;
}
case 2: {
break;
}
case 3: {
break;
}
default: {
printf("n isn't equal to 1, 2, or 3.n");
break;
}
}
system("PAUSE");
return 0;
}


SWITCH CASE 7
#include <iostream>
int main(void)
{
char grade;
cout << "Enter your grade: ";
cin >> grade;
switch (grade)
{
case 'A':
cout << "Your average must be between 90 - 100"
<< endl;
break;
case 'B':
<< endl;
break;
case 'C':
<< endl;
break;
case 'D':
<< endl;
break;
default:
cout << "Your average must be below 60" << endl;
}
return 0;
}


An output
program using Dev C++


In this looping statement, I used “while” looping, and I choose
to show MDAS just as an example for the program to
run. If logical Expression evaluates to true, the
statement executes. The logical Expression is
reevaluated. The body of the loop continues to execute until
thehttp://eglobiotraining.com
logicalExpression is false

I have came up with this by just starting to write this
code: #include <iostream> and then enter the
succeeding codes, compiled and run.


I noticed that sometimes if the program does not run, it is
because some braces are not included and I accidentally
put braces on the same line and it causes the program
not to read its contents. Programming is sensitive, when
there is missing variable or braces or some words it does
not run.

When I learned that programming is very sensitive
and at the same time very detailed when it comes to
entering codes, I make sure that it is clear means that
I put everything important codes in it so that the
program would run.

So much codes that should be entered that even the
spaces are needed programming is very specific that
whatever you have entered in to it you should specify
because when the statement is false it wouldn’t let you run
the program, I have experienced it before I arrived at this
result.

Because of so many experiences I had before this
program run, I found programming is also interesting
for the more you are practicing to make a program run,
the more questions that came up in my mind and try
something that will fit to this or entering new codes to
http://eglobiotraining.com etc… that I know is possible.
make matrix

In this switch case missing out a break statement causes
control to fall through to the next case label. Switches can
always be replaced by nested if-else statements, but in
some cases this may be more clumsy.
Each break statement terminates the
enclosing switch statement. Control flow continues with the

first statement

Unlike if-then and if-then-else statements,
the switch statement can have a number of possible execution
paths, A switch works with the byte, short, char,
and int primitive data types.

The switch statement evaluates its expression, then
executes all statements that follow the matching case label.


The switch statement can include any number
of case instances, but no two case constants within the
same switch statement can have the same value. Execution
of the statement body begins at the selected statement and
proceeds until the jump-statement transfers control out of
the case body.

Submitted to:
Prof. Erwin Globio

Submitted by:
Francisco, Kimberly
BM10203


Switch case and looping kim

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