c++ statements

8/6/2019 C++ Statements

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C++ STATEMENTS

Arvin Anthony S. Araneta



Objectives:

Ou tlines the different statements used

in C++.

Use the different statements in writingprograms.

Prepare correct programs.



Guide Questions:

W hat are the different statements inC++?

W hat is the best statement to use in

C++? W hen for loop is used in a program, is there a possibility in rewriting theprogram so that the while loop isused? the if statement is used? the while statement is used? the do whileloop is used? How?



It permits us t o m odify the instructi on of h ow the statements in our pr ograms are

acc omplished .

Control Flow Statements



T he semicolon is used as a statement

terminator. A null statement is signified by an isolated semicolon. A compound

statement, or block, is a series of

statements enclosed by braces, i.e.,

{

statement1;

statement2;}



Categories of Control Flow Statements:

� Decision Control Structures. Statements that

allows us to select and execu te specific

blocks of code while skipping other sections.

� Repetition Control Structures. Statements

that allows us to execu te specific blocks of

code a number of times.



if if else if else if

switc

Decision Control Structure



if

T he if keyword i s used to execu te a statement

or block or block only if the condi ti on i s

f ulfi lled.

Its f orm i s:

if (expressi on)

statement/s...



if

E xample:

1. if ( a > b)

cou t << "a is greater than b " << endl;

2. if ( a > b)

{ a = a * b;

cou t << "the value of a is " << a << endl;

}



Sample Program for if statement:

#include <iostream>

int main(){

char answer;

cou t << \Do you consider your self a hot-tempered individual

(y=Yes / n=No) ?[ ;

cin >> answer;

if (answer == Zy ) // 1st condition

{

cou t << \\n T his job involves a high level of self-control.[;

cou t << n W e will get back to you!\ n;

}

if (answer == Zn) //2nd condition

cou t << \\ nYou are hired!;

return 0;

}



if ² else

T he if-else statement is used when we want to

execu te a certain statement if a condition is

true, and a different statement if the condition

is false.



if ² else

Its form is:

if (expression)

statement/s...else statement/s...



if ² else

E xample:

1. if (a > b) // if true

cou t << "a is greater than b" << endlelse

cou t << "a is less than or equal to b" <<

endl;



if ² else

E xample:

2. if (x == 100)

cou t << \x is 100" << endlelse

cou t << \x is not 100" << endl;



Sample Program for if else statement:

#include <iostream>

int main(){

char answer;


(y=Yes / n=No) ?[ ;

cin >> answer;


{

cou t << \\ n T his job involves a high level of self-control.[;

cou t << \\ n W e will get back to you!\ n;

}

else // Any other answer


return 0;

}



if ² else if

T he statement in the else-cla use of an if-elseblock can be another if-else structures.

Its form is:

if (expression)

statement/s...

else if

statement/s...else

statements/s



if ² else if

E xample:

1. if (a == 0) // if true

cou t << "a is exactly equal to 0" << endl;else if (a < 0) // if true

cou t << "a is a negative number " << endl

else

cou t << "a is a positive number " << endl;



Sample Program for if else statement:

#include <iostream>

int main(){

char answer;


(y=Yes / n=No) ?[ ;

cin >> answer;


{

cou t << \\ n T his job involves a high level of self-control.[;

cou t << \\ n W e will get back to you!\ n;

}

else if (answer == Zn)


else

cou t << \\ n T hat;s not a valid answer!\ n[;

return 0;

}



switch

Its objective is to check several possible constant

values for an expresion

Its form is:

switch (expression) {

case constant_expression: statement/s

case constant_expression: statement/s

/* as many cases as needed... */defa ult: statements

}



switch

E xample:1. switch (MyChoice) {

case 'a': {

cou t << " T hecharacter is a. " <<endl;

break; }

case 'X': {

cou t << " T he

character is X. " <<endl;

break; }

case 'j': {

cou t << " T he character is

j. " << endl;

break; }

defa ult: {

cou t << "Invalidentry !WPress any key W " << endl;

break; }}



Sample Program for switch statement:

#include <iostream>

int main(){

int number;

cou t << \ T ype a number between 1 and 3: \;

cin >> number;

switch (number)

{case 1:

cou t << \You type 1.[;

case 2:

cou t << \You type 2.[;

case 3:

cou t << \You type 3.[;defa ult:

cou t << endln << Number << \ is not of therequested range! \;

}

return 0;

}



while for

do h while

Repetition Control Structure



while

A statement or block of statements that is

repeated as long as some condition is

satisfied.

Its form is:

while (expression)

statement/s



while

E xample

1. a = 1;

while ( a <= 10)

{

cou t << a << endl; a ++;

}



Sample Program for while statement:

#include <iostream>int main()

{

int number; // = 0

while (number < = 12)

{

cou t << \Number \ << Number << endln;

number ++;

}

return 0;

}



for

T he for statement is typically used to count a

number of items. At its regular structure, it is

divided into three parts:

� T he first section specifies the starting point for

the count.

� T he second section sets the counting limit.

� T he last section determines the counting frequency.



for

Its form is:

for (InitializationE xpression;

LoopCondition;StepE xpression)

{

statement1;

statement2;

. . .}



Sample Program for for statement:

#include <iostream>int main()

{

for (int count =0; count <= 12; count++)

cou t << \Number \ << count << endln;

return 0;

}



do ² while

� Statements inside a do-while loop are

execu ted several times as long as the

condition is satisfied.

� Its form is:

do {

statement/s...

} while (expression);



do ² while

E xample

1. do

cou t << Number \ << Number ++

<< endln;

while (number <= 12)



Sample Program for for statement:

#include <iostream>

int main()

{

unsigned long n;

do{

cou t << \Enter number (0 to end) \;

cin >> n;

cou t << \you entered: \; << n << endln;

} while (n != 0);

return 0;

}



Drills

Construct a program that will display the

multiplication table of 10.

c++ statements

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