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Page 1: Branching Statements• The else-if statement is a shorthand for an if-statement in the body of the else of another if-statement • Else-if statements require first an if-statement
Page 2: Branching Statements• The else-if statement is a shorthand for an if-statement in the body of the else of another if-statement • Else-if statements require first an if-statement

Branching StatementsPart 02

Page 3: Branching Statements• The else-if statement is a shorthand for an if-statement in the body of the else of another if-statement • Else-if statements require first an if-statement

• Some statements can be nested within the body of another statement

• Nested if-statements are if-statements within the body of another if-statement– Same is true with if-else statements– Else statements still must have a

corresponding if-statement

• Very useful when testing a combination of conditions

Syntax

if(<<Boolean expression>>){

if(<<Boolean expression>>){

…}

}

Exampleif(a == b){

System.out.println(“a is equal to b”);if(b == c){

System.out.println(“b is equal to c”);}else{

System.out.println(“b is not equal to c”);}

}

Page 4: Branching Statements• The else-if statement is a shorthand for an if-statement in the body of the else of another if-statement • Else-if statements require first an if-statement

General Nested If-Statement Flow ChartSyntax

if(<<Boolean expression 1>>){

if(<<Boolean expression 2>>){

//Body of nested if}else{

//Body of nested else}

}else{

//Body of else}

Body of else

true falseBoolean Expression

1

Boolean Expression

2

true false

Body of nested if

Body of nested

else

Page 5: Branching Statements• The else-if statement is a shorthand for an if-statement in the body of the else of another if-statement • Else-if statements require first an if-statement

if(a == b){

if(b == c)e = f;

}else

e = g;

• You may omit the curly braces whenever an if-statement or else-statement has exactly ONE statement in its body

• An if-else is considered as one statement in Java

• This may cause logic errors if not careful• It’s a good idea to put the curly braces to

clearly define the body of the statements• The 2 examples do not have the same logic

if(a == b)if(b == c)

e = f;else

e = g;

Page 6: Branching Statements• The else-if statement is a shorthand for an if-statement in the body of the else of another if-statement • Else-if statements require first an if-statement

if(a == b){

if(b == c)e = f;

}else

e = g;

• You may omit the curly braces whenever an if-statement or else-statement has exactly ONE statement in its body

• An if-else is considered as one statement in Java

• This may cause logic errors if not careful• It’s a good idea to put the curly braces to

clearly define the body of the statements• The 2 examples do not have the same logic

if(a == b)if(b == c)

e = f;else

e = g;//Whoops!

Page 7: Branching Statements• The else-if statement is a shorthand for an if-statement in the body of the else of another if-statement • Else-if statements require first an if-statement

• The else-if statement is a shorthand for an if-statement in the body of the else of another if-statement

• Else-if statements require first an if-statement– Just like an else-statement

• Can have multiple else-if statements in succession

• For the statements in an else-if to run the previous if’s or else-if’s must be false– Else-if’s should only be used when the

conditions are dependent

Syntax

if(<<Boolean expression>>){

//Body of if-statement}else if(<<Boolean expression>>){

//Body of else-if statement}else{

//Body of else statement}

Exampleif(a == b){

System.out.println(“a is equal to b”);}else if(a == c){

System.out.println(“a is equal to c, and not b”);}else{

System.out.println(“a is not equal to b or c”);}

Page 8: Branching Statements• The else-if statement is a shorthand for an if-statement in the body of the else of another if-statement • Else-if statements require first an if-statement

General Nested Else-If-Statement Flow ChartSyntax

if(<<Boolean expression 1>>){

//Body of if}else if(<<Boolean expression 2>>){

//Body of else-if}else{

//Body of else}

Body of else

true falseBoolean Expression

1

Boolean Expression

2

true falseBody of nested if

Body of else-if

Page 9: Branching Statements• The else-if statement is a shorthand for an if-statement in the body of the else of another if-statement • Else-if statements require first an if-statement

if (Boolean_Expression_1){

Statement_1}else if (Boolean_Expression_2){

Statement_2}else if (Boolean_Expression_3){

Statement_3}else{

Default_Statement}

if (Boolean_Expression_1){

Statement_1}else{

if (Boolean_Expression_2) {

Statement_2}else{

if(Boolean_Expression_3){

Statement_3}else{

Default_Statement}

}}

Page 10: Branching Statements• The else-if statement is a shorthand for an if-statement in the body of the else of another if-statement • Else-if statements require first an if-statement

if (Boolean_Expression_1){

Statement_1}else if (Boolean_Expression_2){

Statement_2}else if (Boolean_Expression_3){

Statement_3}else{

Default_Statement}

if (Boolean_Expression_1){

Statement_1}if (Boolean_Expression_2){

Statement_2}if (Boolean_Expression_3){

Statement_3}else{

Default_Statement}

Page 11: Branching Statements• The else-if statement is a shorthand for an if-statement in the body of the else of another if-statement • Else-if statements require first an if-statement
Page 12: Branching Statements• The else-if statement is a shorthand for an if-statement in the body of the else of another if-statement • Else-if statements require first an if-statement

Let’s Make a Decision!

Page 13: Branching Statements• The else-if statement is a shorthand for an if-statement in the body of the else of another if-statement • Else-if statements require first an if-statement
Page 14: Branching Statements• The else-if statement is a shorthand for an if-statement in the body of the else of another if-statement • Else-if statements require first an if-statement

Contestant 1

Page 15: Branching Statements• The else-if statement is a shorthand for an if-statement in the body of the else of another if-statement • Else-if statements require first an if-statement

Contestant 1 Contestant 2

Page 16: Branching Statements• The else-if statement is a shorthand for an if-statement in the body of the else of another if-statement • Else-if statements require first an if-statement

Contestant 1 Contestant 2

Box #1 Box #2 Box #3

Page 17: Branching Statements• The else-if statement is a shorthand for an if-statement in the body of the else of another if-statement • Else-if statements require first an if-statement

Contestant 1 Contestant 2

Box #1 Box #2 Box #3

Page 18: Branching Statements• The else-if statement is a shorthand for an if-statement in the body of the else of another if-statement • Else-if statements require first an if-statement

Contestant 1 Contestant 2

Box #1 Box #2 Box #3

Page 19: Branching Statements• The else-if statement is a shorthand for an if-statement in the body of the else of another if-statement • Else-if statements require first an if-statement

Contestant 1 Contestant 2

Box #1 Box #3

Page 20: Branching Statements• The else-if statement is a shorthand for an if-statement in the body of the else of another if-statement • Else-if statements require first an if-statement

Contestant 1 Contestant 2

Box #3

Page 21: Branching Statements• The else-if statement is a shorthand for an if-statement in the body of the else of another if-statement • Else-if statements require first an if-statement

Contestant 1 Contestant 2

Page 22: Branching Statements• The else-if statement is a shorthand for an if-statement in the body of the else of another if-statement • Else-if statements require first an if-statement

THANK YOU FORPLAYING!

Page 23: Branching Statements• The else-if statement is a shorthand for an if-statement in the body of the else of another if-statement • Else-if statements require first an if-statement

• The “?” and the “:” together are called the conditional opertator– AKA ternary operator– AKA “One-line if”

• The value after the “?” corresponds to the body of the if-statement

• The value after the “:” corresponds to the body of the else-statement

• Can be useful for writing print statements

Syntax

<<var>> = (<<Boolean expression>>)?<<value 1>>:<<value 2>>;

Example

maxValue = (value1 >= value2) ? Value1 : value2;

Page 24: Branching Statements• The else-if statement is a shorthand for an if-statement in the body of the else of another if-statement • Else-if statements require first an if-statement

Syntax

System.exit(<<Integer Value>>);

• The exit method immediately stops the program

• Can be used when there arises an error that will prevent a program from working

• The value “0” is generally used when the program is exiting under normal conditions

Exampleif(!validInput){

System.exit(0);}

Page 25: Branching Statements• The else-if statement is a shorthand for an if-statement in the body of the else of another if-statement • Else-if statements require first an if-statement

Highest Precedence

Lowest Precedence

Unary Operators +, -, ++, --, !

Binary Arithmetic * , /, %

Binary Arithmetic +, -

Boolean Operators <, >, <=, >=

Boolean Operators ==, !=

Boolean Operator &

Boolean Operator |

Boolean Operator &&

Boolean Operator ||

Page 26: Branching Statements• The else-if statement is a shorthand for an if-statement in the body of the else of another if-statement • Else-if statements require first an if-statement

Example 1boolean a = false;boolean b = true;if(a && b)//b is never checked{

}

• Sometimes only a part of a Boolean expression needs to be evaluated to determine the entire value– If the first operand of an && is false, then the

entire expression is false– If the first operand of an || is true, then the

entire expression is true

• Sometimes called Lazy Evaluation• Very efficient and sometimes necessary

Example 2boolean a = true;boolean b = false;if(a || b)//b is never checked{

}


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