Mark asoi ppt

Switch case
And
Looping

Submitted by:
Mark Kazuyoshi P. Asoi

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.
http://eglobiotraining.com 2

Computer Programming (often shortened
to Programming or coding) is the process of designing,
writing, testing, debugging, and maintaining the source
code of computer programs. This source code is written in one or
more Programming Language (such as Java, C++, C#, Python,
etc.). The purpose of Programming is to create a set of
instructions that computers use to perform specific operations or
to exhibit desired behaviors. The process of writing source code
often requires expertise in many different subjects, including
knowledge of the application domain,
specialized algorithms and formal logic.


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 browser…

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.


Within software engineering, Programming (the implementation)
is regarded as one phase in a software development process.
There is an ongoing debate on the extent to which the writing of
programs is an art form, a craft or an engineering discipline.] In
general, good Programming is considered to be the measured
application of all three, with the goal of producing an efficient and
evolvable software solution (the criteria for "efficient" and
"evolvable" vary considerably). The discipline differs from many
other technical professions in that programmers, in general, do
not need to be licensed or pass any standardized (or
governmentally regulated) certification tests in order to call
themselves "programmers" or even "software engineers."
Because the discipline covers many areas, which may or may not
include critical applications, it is debatable whether licensing is
required for the profession as a whole. In most cases, the
discipline is self-governed by the entities which require the
Programming, and sometimes very strict environments are
defined (e.g. United States Air Force use of AdaCore and security
clearance). However, representing oneself as a "Professional
Software Engineer" without a license from an accredited
institution is illegal in many parts of the world.

Another ongoing debate is the extent to which the Programming
language used in writing computer programs affects the form that
the final program takes. This debate is analogous to that
surrounding the Sapir–Whorf hypothesis in
linguistics and cognitive science, which postulates that a
particular spoken language's nature influences the habitual
thought of its speakers. Different language patterns yield different
patterns of thought. This idea challenges the possibility of
representing the world perfectly with language, because it
acknowledges that the mechanisms of any language condition
the thoughts of its speaker community.


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).

but there is really very little left to know about Programming
itself. Most of the rest of C is concerned with making the
business of Programming simpler. A good example of this is
the switch construction.


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.

but there is really very little left to know about Programming itself.
Most of the rest of C is concerned with making the business of
Programming simpler. A good example of this is
the switch construction.


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.

In a loop structure, the program asks a question, and if the
answer requires an action, it is performed and the original
question is asked again until the answer is such that the
action is no longer required.

In a loop structure, the program asks a question, and if
the answer requires an action, it is performed and the
original question is asked again until the answer is such
that the action is no longer required.


(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.


#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.


#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".


#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.


Condition and
Explanation of the
Programs that have
been tested


Switch case 1
#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 2

#include <stdio.h>

main() {

int grade;
printf ("Input grade :");
scanf("%d", & grade);

switch (grade) {

case 1:
printf("Fall (F)n");break;
case 2:
printf("Bad (D)n");break;
case 3:
printf("Good (C)n");break;
case 4:
printf("Very Good (B)n");break;
case 5:
printf("Excellent (A)n");break;
default:
printf("You have inputted false graden");
break; // break isn’t necessary here
}
}


#include <iostream>

Switch case 3 using namespace std;

int main ()

{

int score;

cout << "What was your score?";

cin >> score;

if (score <= 25)

{

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

}

else if (score <= 50)

{

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

}


{

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

}


{

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

}

else
{

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

}

cin.ignore();

cin.get();

return 0;

} http://eglobiotraining.com 28

Switch case 4

#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;
}


Switch case 5

#include <stdio.h>
#include <math.h>

main() {

int i, n, prime=1; // prime is true

printf("Input natural number :");
scanf("%d", &n);

for( i=2; i<= n-1; i++) {

if( n % i == 0 ) { // also possible to state if(!(n % i))

prime =0; // prime is now false
break;

}
}

if( prime )

printf("%d is prime number !n", n);

else

printf("%d isn’t prime number!n", n);

}


Looping Statement 1

#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 2
#include <stdio.h>

main()

{ float price;

short quantity;

char answer;

do

{ printf("Enter 'price quantity': ");

scanf("%f %hi", &price, &quantity);

printf("The total for this item is $%6.2f.n", price * quantity);

printf("Another (Y/N)? ");

scanf(" %c", &answer);

}while ("answer == 'Y' | | answer == 'y'");

printf("Thank you for your patronage.n");

}


Looping Statement 3
#include <stdio.h>

main()

{ float price;

short quantity;

char answer;

printf("Do you wish to enter a purchase (Y/N)? ");


while ("answer == 'Y' | | answer == 'y'")

{ printf("Enter 'price quantity': ");

scanf("%f %hi", &price, &quantity);

printf("The total for this item is $%6.2f.n", price * quantity);

printf("Another (Y/N)? ");


}

printf("Thank you for your patronage.n");

}

Looping Statement 4

#include<iostream>

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

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

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


Looping Statement 5

//
// Demonstrates do while

#include <iostream.h>

int main()
{
int counter;
cout << "How many hellos? ";
cin >> counter;
do
{
cout << "Hellon";
counter--;
} while (counter >0 );
cout << "Counter is: " << counter << endl;
return 0;
}


An Output
Program using
Dev C++


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 make matrix etc… that I know is possible.

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 http://eglobiotraining.com 38

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.

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.


Switch case is substitute for long if statements that compare a variable
to several "integral" values that can be expressed as an integer,


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.


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.


Being able to have your program repeatedly execute a block of
code is one of the most basic but useful tasks in Programming


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


The do...while loop executes the body of the loop before its condition
is tested and ensures that the body always executes at least one time.
What if you want to ensure that Hello is always printed at least once?
The while loop can't accomplish this, because the if condition is tested
before any printing is done. You can force the issue with
an if statement just before entering the while:

Submitted to:
Professor.
Erwin Globio

Official Website:

http://eglobiotraining.com/


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