Control Statementss

7/29/2019 Control Statementss

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Three control structures

selection/decision structures:- checks the

given condition and then execute its sub-

block.

if, ifelse,nested if, ladder if, switch

Repetition/loop structures:- statements

which are repeatedly executed for certain no

of times.

while, dowhile, for

Jumping statements:-goto,break,continue


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A simple ifstructure is called a single-selectionstructure because it either selects or ignores asingle action.

The if / else structure is called a double-selection structure because it selects betweentwo different actions.

Nested if / else structures test for multiple cases

by placing if / else structures inside other if /else structures.

The ladder if /else ifstructure test for multiplecases by placing different conditions in else if.


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Syntax:- if(condition)

{

------------------;

-------------------;

}


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include

#include

void main()

{

int age;

clrscr();

Coutage;

if(age>17){

Cout


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Syntax:- if(condition){

-----------------;

-------------------;

}

else

{

-----------------;

-------------------;}


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#include

#include

void main(){

int age;

clrscr();

Coutage;

if(age>17)

{

Cout


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Syntax:- if(condition)

{

If(){

}

Else

{

}

}

else

{

If()

{

}

Else

{

}

}


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Void main()

{

Int a=10,b=20,c=30;

If(a>b)

{

If(a>c)

{

cout


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Syntax:-

if (cond1)

{

statement1;

}

else if (cond2)

{

statement2;

}

else if (cond n)

{statement n;

}

else

statement;


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if ( studentGrade >= 90 )

cout = 80 )cout = 70 )

cout = 60 )

cout


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Compound statement Also called a block Set of statements within a pair of braces Used to include multiple statements in an if body

Example if ( studentGrade >= 60 )

cout


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Similar to if statements

Can list any number of branches

Used in place of nested if statements

Avoids confusion of deeply nested ifsMultiple way branch statement

Used for multiple selections

Tests a variable or expression

Compared against constant integral expressions to

decide on action to take


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Syntax:-switch (expression) {

case value1:statement1;

break;case value2:

statement2;break;

case valuen:statementn;break;

default:statement;}


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switch statement

Controlling expression

Expression in parentheses after keyword switch

case labels Compared with the controlling expression

Statements following the matching case label areexecuted

Braces are not necessary around multiple statements in a

case label A break statements causes execution to proceed with the

first statement after the switch

Without a break statement, execution will fall throughto the next case label


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switch statement (Cont.)

default case

Executes if no matching case label is found

Is optional

If no match and no default case

Control simply continues after the switch


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Char grade;

Cin>>grade;

switch (grade)

{

case A:

cout


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* * * * Menu * * * *

1. add

2. mul3. div

4. sub

Choose either 1, 2, 3 or 4:


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Int ch,a=10,b=20;cin>>ch;

switch (ch)

{

case 1:

cout


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While

Do while

for


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while loop repeats until condition becomesfalse

int count =1;

int total = 0;while (count


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dowhilestatement Similar to while statement

Tests loop-continuation after performing bodyof loop Loop body always executes at least once

Code: x=10;

do

{

cout


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for repetition statement

Specifies counter-controlled repetition details in

a single line of code


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Not Valid:

X for (j = 0, j < n, j = j + 3) // semicolons needed

for (j = 0; j < n) // three parts needed


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for statement examples

Vary control variable from 1 to 100 in increments of1

for ( int i = 1; i = 1; i-- )

Vary control variable from 7 to 77 in steps of7

for( int i = 7; i = 2; i -= 2 )

Vary control variable over the sequence: 2, 5, 8, 11,14, 17, 20

for( int i = 2; i = 0; i -= 11 )


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Using a comma-separated list of

expressions

for ( int number = 2;number


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Example 3: j = 1;sum = 0;for ( ; ; ){ sum = sum + j; j++;

printf"\n"


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General form of the for statement

for ( initialization; loopContinuationCondition;increment)

statement;

Can usually be rewritten as: initialization;while ( loopContinuationCondition)

{statement;

increment;}

If the control variable is declared in the initialization

expression

It will be unknown outside the for statement


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break statement

Causes immediate exit from the loop

Used in while, for, dowhile or switchstatements

continue statement

Skips remaining statements in loop body and

start from the beginning of loop

Used in for loop, while , dowhile loops


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void main ( ){

int k;for ( k= -5; k < 25; k= k+5){

cout


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void main ( )

{

int k;

for ( k= -5; k < 25; k= k+5)

{

cout


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Void main ( ){

int k;

for ( k= -5; k < 25; k= k+5)

{

cout


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int j =50;while (j < 80)

{j += 10;if (j == 70)break;

cout


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#include

#include int main() {

int n = 0;loop:

cout


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It is used to return the value to the calling

function.

It can be used in fallowing ways

a) return(expression) return(a+b);b) A function may use one or more return

statement depending upon condition

if(a>b)

return(a);

else

return(b);

Date post:	14-Apr-2018
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Control Statementss

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