assignment c++ mohammad nazrul hadi bin mohamad amran

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ASSINGMENT C++ MOHAMMAD NAZRUL HAD BIN MOHAMAD AMRAN MAY 4, 2016 IT-SKN-1A INSTITUT KEMAHIRAN MARA LUMUT

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Page 1: assignment C++ MOHAMMAD NAZRUL HADI BIN MOHAMAD AMRAN

ASSINGMENT C++ MOHAMMAD NAZRUL HAD BIN MOHAMAD AMRAN

MAY 4, 2016 IT-SKN-1A

INSTITUT KEMAHIRAN MARA LUMUT

Page 2: assignment C++ MOHAMMAD NAZRUL HADI BIN MOHAMAD AMRAN

1. Who is Written C++?

Stroustrup began developing C++ in 1978

(then called "C with Classes"), and, in his own

words, "invented C++, wrote its early definitions,

and produced its first implementation... chose and

formulated the design criteria for C++, designed all

its major facilities, and was responsible for the

processing of extension proposals in the C++

standards committee."[11] Stroustrup also

wrote a textbook for the language, The C++ Programming Language.

Stroustrup was the head of AT&T Bell Labs' Large-scale Programming

Research department, from its creation until late 2002. Stroustrup was elected

member of the National Academy of Engineering in 2004. He is a Fellow of the

ACM (1994) and an IEEE Fellow. He works at Texas A&M University as a

Distinguished Professor where he holds the College of Engineering Endowed

Chair in Computer Science.[12][13] He is also a visiting faculty in Computer

Science Department at Columbia University.[14] ITMO University noble doctor

since 2013[15]

In 2015, he was made a Fellow [16] of the Computer History Museum for his

invention of the C++ programming language.

Page 3: assignment C++ MOHAMMAD NAZRUL HADI BIN MOHAMAD AMRAN

2. State statements below and give an example application

in C++ Program.

a. C++ go to Statement

In C++ programming, goto statement is used for altering the normal sequence of program

execution by transferring control to some other part of the program.

Syntax of goto Statement

goto label;

... .. ...

... .. ...

... .. ...

label:

statement;

... .. ...

In syntax above, label is an identifier. When goto label; is encountered, the control of

program jumps to label: and executes the code below it.

Page 4: assignment C++ MOHAMMAD NAZRUL HADI BIN MOHAMAD AMRAN

Example 1: goto Statement

/* C++ program to demonstrate the working of goto statement. */

/* This program calculates the average of numbers entered by user. */

/* If user enters negative number, it ignores that number and

calculates the average of number entered before it.*/

# include <iostream>

using namespace std;

int main() {

float num, average, sum = 0.0;

int i, n;

cout<<"Maximum number of inputs: ";

cin>>n;

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

cout<<"Enter n"<<i<<": ";

cin>>num;

if(num < 0.0) {

goto jump; /* Control of the program moves to jump; */

}

sum += num;

}

jump:

average=sum/(i-1);

cout<<"\nAverage = "<<average;

return 0;

}

Output

Maximum number of inputs: 10

Enter n1: 2.3

Enter n2: 5.6

Enter n3: -5.6

Average = 3.95

You can write any C++ program with use of goto statement and it is generally considered good idea

not to use goto statement.

Reason to Avoid goto Statement

The goto statement gives power to jump to any part of program but, makes the logic of the program

complex and tangled. In modern programming, goto statement is considered a harmful construct and a

bad programming practice.

The goto statement can be replaced in most of C++ program with the use of break and continue

statements.

Page 5: assignment C++ MOHAMMAD NAZRUL HADI BIN MOHAMAD AMRAN

b. While 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 : c)

Break and Continue It causes the execution flow to jump around and because

it can make the flow of logic harder to follow Example :

Page 6: assignment C++ MOHAMMAD NAZRUL HADI BIN MOHAMAD AMRAN

c. C++ break and continue Statement

There are two statements (break; and continue;) built in C++ programming to alter

the normal flow of program.

Loops are used to perform repetitive task until test expression is false but sometimes it

is desirable to skip some statement/s inside loop or terminate the loop immediately with

checking test condition. On these type of scenarios, continue; statement and break;

statement is used respectively. The break; statement is also used to terminate switch

statement.

C++ break Statement

The break; statement terminates the loop(for, while and do..while loop) and switch

statement immediately when it appears.

Syntax of break

break;

In real practice, break statement is almost always used inside the body of conditional

statement(if...else) inside the loop.

Working of break Statement

Page 7: assignment C++ MOHAMMAD NAZRUL HADI BIN MOHAMAD AMRAN

Example 1: C++ break

C++ program to add all number entered by user until user enters 0.

// C++ Program to demonstrate working of break statement

#include <iostream>

using namespace std;

int main() {

float number, sum = 0.0;

while (true) { // test expression is always true

cout<<"Enter a number: ";

cin>>number;

if (number != 0.0) {

sum += number;

}

else {

break; // terminating the loop if number equals to 0.0

}

}

cout<<"Sum = "<<sum;

return 0;

}

Output

Enter a number: 4

Enter a number: 3.4

Enter a number: 6.7

Enter a number: -4.5

Enter a number: 0

Sum = 9.6

In this C++ program, the test expression is always true. The user is asked to enter a

number which is stored in variable number. If the user enters any number other than 0,

that number is added to sum and stored to it and again user is asked to enter another

number. When user enters 0, the test expression inside if statement is false and body of

else is executed which terminates the loop. Finally, the sum is displayed.

C++ continue Statement

It is sometimes necessary to skip some statement/s inside the loop. In that case,

continue; statement is used in C++ programming.

Syntax of continue

continue;

In practice, continue; statement is almost always used inside conditional statement.

Page 8: assignment C++ MOHAMMAD NAZRUL HADI BIN MOHAMAD AMRAN

Working of continue Statement

Example 2: C++ continue

C++ program to display integer from 1 to 10 except 6 and 9.

// C++ Program to demonstrate working of continue statement

#include <iostream>

using namespace std;

int main() {

for (int i = 1; i <= 10; ++i) {

if ( i == 6 || i == 9) {

continue;

}

cout<<i<<"\t";

}

return 0;

}

Output

1 2 3 4 5 7 8 10

In above program, when i is 6 or 9, execution of statement cout<<i<<"\t"; is skipped

inside the loop using continue; statement.

Page 9: assignment C++ MOHAMMAD NAZRUL HADI BIN MOHAMAD AMRAN

d. While True I'm curious about using a while statement with a true condition. What is the

advantage of using a while(true) statement with break to exit the while statement

over something like a for loop? I guess I'm just curious when a good time to use

this technique would be? I saw it demonstrated in a quick sort algorithm at school

today and was just curious about it. Insight? Example : e) Do \ White The

do...while Loop is similar to while loop with one very important difference. In

while loop, check expression is checked at first before body of loop but in case of

do...while loop, body of loop is executed first then only test expression is

checked. That's why the body of do...while loop is executed at least once.

Example :

Page 10: assignment C++ MOHAMMAD NAZRUL HADI BIN MOHAMAD AMRAN

e. Do while statements

One interesting thing about the while loop is that if the loop condition is initially false, the

while loop will not execute at all. It is sometimes the case that we know we want a loop to

execute at least once, such as when displaying a menu. To help facilitate this, C++ offers

the do-while loop:

do

statement;

while (condition);

The statement in a do-while loop always executes at least once. After the statement has

been executed, the do-while loop checks the condition. If the condition is true, the CPU

jumps back to the top of the do-while loop and executes it again.

Here is an example of using a do-while loop to display a menu to the user and wait for the

user to make a valid choice:

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

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26

#include <iostream>

int main()

{

// selection must be declared outside do/while loop

int selection;

do

{

std::cout << "Please make a selection: \n";

std::cout << "1) Addition\n";

std::cout << "2) Subtraction\n";

std::cout << "3) Multiplication\n";

std::cout << "4) Division\n";

std::cin >> selection;

}

while (selection != 1 && selection != 2 &&

selection != 3 && selection != 4);

// do something with selection here

// such as a switch statement

std::cout << "You selected option #" << selection << "\n";

return 0;

}

One interesting thing about the above example is that the selection variable must be

declared outside of the do block. Why do you think that is?

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If the selection variable were to be declared inside the do block, it would be destroyed

when the do block terminates, which happens before the while conditional is executed.

But we need the variable to use in the while conditional -- consequently, the selection

variable must be declared outside the do block.

Generally it is good form to use a do-while loop instead of a while loop when you

intentionally want the loop to execute at least once, as it makes this assumption explicit

-- however, it’s not that big of a deal either way.

f. Jump \ Loop

Cause a certain piece of program to be executed a certain number of times. Consider these

scenarios:

-You want to execute some code/s certain number of time.

-You want to execute some code/s certain number of times depending upon input from user.

Example :

Page 12: assignment C++ MOHAMMAD NAZRUL HADI BIN MOHAMAD AMRAN

Output :

g. C++ if/else statement

An if statement can be followed by an optional else statement, which executes when the

boolean expression is false.

Syntax:

The syntax of an if...else statement in C++ is:

if(boolean_expression)

{

// statement(s) will execute if the boolean expression is true

}

else

{

// statement(s) will execute if the boolean expression is false

}

If the boolean expression evaluates to true, then the if block of code will be executed,

otherwise else block of code will be executed.

Page 13: assignment C++ MOHAMMAD NAZRUL HADI BIN MOHAMAD AMRAN

Flow Diagram:

Example:

#include <iostream>

using namespace std;

int main ()

{

// local variable declaration:

int a = 100;

// check the boolean condition

if( a < 20 )

{

// if condition is true then print the following

cout << "a is less than 20;" << endl;

}

else

{

// if condition is false then print the following

cout << "a is not less than 20;" << endl;

}

cout << "value of a is : " << a << endl;

return 0;

}

When the above code is compiled and executed, it produces the following result:

a is not less than 20;

value of a is : 100

Page 14: assignment C++ MOHAMMAD NAZRUL HADI BIN MOHAMAD AMRAN

The if...else if...else Statement:

An if statement can be followed by an optional else if...else statement, which is very

usefull to test various conditions using single if...else if statement.

When using if , else if , else statements there are few points to keep in mind.

An if can have zero or one else's and it must come after any else if's.

An if can have zero to many else if's and they must come before the else.

Once an else if succeeds, none of he remaining else if's or else's will be tested.

Syntax:

The syntax of an if...else if...else statement in C++ is:

if(boolean_expression 1)

{

// Executes when the boolean expression 1 is true

}

else if( boolean_expression 2)

{

// Executes when the boolean expression 2 is true

}

else if( boolean_expression 3)

{

// Executes when the boolean expression 3 is true

}

else

{

// executes when the none of the above condition is true.

}

Example:

#include <iostream>

using namespace std;

int main ()

{

// local variable declaration:

int a = 100;

// check the boolean condition

if( a == 10 )

{

// if condition is true then print the following

cout << "Value of a is 10" << endl;

}

else if( a == 20 )

{

// if else if condition is true

cout << "Value of a is 20" << endl;

}

else if( a == 30 )

{

Page 15: assignment C++ MOHAMMAD NAZRUL HADI BIN MOHAMAD AMRAN

// if else if condition is true

cout << "Value of a is 30" << endl;

}

else

{

// if none of the conditions is true

cout << "Value of a is not matching" << endl;

}

cout << "Exact value of a is : " << a << endl;

return 0;

}

When the above code is compiled and executed, it produces the following result:

Value of a is not matching

Exact value of a is : 100