Java conditional statements

if, else if, nested if, switch case, break, continue statements
Type conversion or Typecasting

1. Conditional Statements
&
Type Conversion in JAVA
Dr. Kuppusamy.P
Associate Professor / SCOPE

2. ConditionalStatements
•ConditionalStatementsexecutesoneorsetofstatementsbasedona
conditionexactlyonce.
•TherearefourtypesofConditionalStatementsinjava
•Simpleif
•else..if
•Nestedelse…if
•Switchcasestatements
Dr. Kuppusamy P

3. Simpleifstatement
•syntax:
if(booleanexpression)
{
statement–block;
}
Otherstatements;
Dr. Kuppusamy P

4. Simpleifstatement
/*Thisisanexampleofsimpleifstatement*/
publicclassSampleTest
{
publicstaticvoidmain(Stringargs[])
{
inta=4;
intb=20;
if(a<b)
{
System.out.println("Thisisifstatement");
}
}
}
Dr. Kuppusamy P

5. if….elsestatement
•Theisanextensionofsimpleifstatement
•syntax:
if(Booleanexpression)
{
True-blockstatements;
}
else
{
False-blockstatements;
}
Otherstatement;
Dr. Kuppusamy P

6. if….elsestatements
/*Exampleofifelsestatement*/
publicclassSampleTest
{
publicstaticvoidmain(Stringargs[])
{
Scannersin=newScanner(System.in);
intage=sin.nextInt();
if(age>40)
{
System.out.println("EligibletoCovidVaccinate")
}
else
{
System.out.println("NotEligibletoCovidVaccinate");
}
}
}
Dr. Kuppusamy P

7. ConditionalOperator
•Conditionaloperatorisanonelinealternativeforifelsecondition.
•Theresultofconditionalstatementscanbestoredintoavariable
•syntax:
condition?truestatements:falsestatements;
•Example:
Stringresult=age>=40?”eligible”:”noteligible”;
Dr. Kuppusamy P

8. Cascading(Nested)if….else
Syntax:
if(condition1)
{
statement-1
}
.
.
.
elseif(condition)
{
statement-n
}
else
{
defaultstatement
}
otherstatement
Dr. Kuppusamy P

9. Cascadingif….elseExample
publicclassCascasdeTest
{
publicstaticvoidmain(Stringargs[])
{
Scannersin=newScanner(System.in);
intmonth=sin.nextInt();
if(month==12||month==1||month==2)
System.out.println("Winter");
elseif(month==3||month==4||month==5)
System.out.println("Spring");
elseif(month==6||month==7||month==8)
System.out.println("Summer");
elseif(month==9||month==10||month==11)
System.out.println("Autumn");
else
System.out.println("invalidmonth");
}
} Dr. Kuppusamy P

10. SwitchCase
Syntax:
switch(expression)
{
casevalue-1:
case-1block
break;
casevalue-2:
case-2block
break;
default:
defaultblock
break;
}
statement-x;
Dr. Kuppusamy P
•Testingformultipleconditions

11. SwitchCase
publicclassSwitchCaseTest
{
publicstaticvoidmain(Stringargs[])
{
Scannersin=newScanner(System.in);
intweekday=sin.nextInt();
switch(weekday){
case1:System.out.println(“Sunday");
break;
case2:System.out.println(“Monday");
break;
case3:System.out.println(“Tuesday");
break;
case4:System.out.println(“Wednesday");
break;
case5:System.out.println(“Thursday");
break;
case6:System.out.println(“Friday");
break;
case7:System.out.println(“Saturday");
break;
default:
System.out.println(“Invalidday");}
}
}
Dr. Kuppusamy P

12. breakstatement
•Thebreakstatementwillterminatetheiterationorswitchcase
blockduringtheexecutionofprogram,
•Whenabreakstatementisencounteredinaloop,theloopexit
andtheprogramcontinueswiththestatementsimmediately
followingtheloop
•Whentheloopsarenested,thebreakwillonlyterminatethe
correspondingloopbody
Dr. Kuppusamy P

13. Quiz
classQuizExample{
publicstaticvoidmain(Strings[]){
if(100>145){
System.out.println("100isgreaterthan145");
}
else
System.out.println("145isgreaterthan100");
}
}
Dr. Kuppusamy P

14. TypeCastinginJAVA
•Typecastingisconvertingavalueofoneprimitivedatatypeto
anothertypeduringanyoperation.
•Twotypesofcasting:
•WideningCasting(automatic)-convertingasmallersizedata
typetoalargersizedatatype
byte->short->char->int->long->float->double
•NarrowingCasting(manual)-convertingalargersizedatatype
toasmallersizedatatype.
double->float->long->int->char->short->byte
Dr. Kuppusamy P

15. WideningTypeCasting(automatic)
publicclassTypecast1
{
publicstaticvoidmain(String[]args)
{
intmyInt=12;
doublemyDouble=myInt;//Automaticcasting:inttodouble
System.out.println(myInt);//Outputs12
System.out.println(myDouble);//Outputs12.0
}
}
Dr. Kuppusamy P

16. NarrowingorExplicitTypeCasting(Manual)
•Assignsavalueoflargerdatatypetoasmallerdatatype.
•usefulforincompatibledatatypeswhereautomaticconversioncannotbe
done.
•Targetdatatypehavetoberepresentedin()nexttothe=sybmbol.
publicclassTypecast2
{
publicstaticvoidmain(String[]args)
{
doublemyDouble=2.35
intmyInt=(int)myDouble;//Manualcasting:doubletoint
System.out.println(myDouble);//Outputs2.35
System.out.println(myInt);//Outputs2
}
}
Dr. Kuppusamy P

17. NarrowingorExplicitTypeCasting(Manual)
publicclassTypecast3
{
publicstaticvoidmain(String[]args)
{
doublea=1232.35
longk=(long)a;//Manualcasting
intj=(int)k;
System.out.println(a);//Outputs1232.35
System.out.println(k);//Outputs1232
System.out.println(j);//Outputs1232
}
}
Dr. Kuppusamy P

18. Stringtointeger
//incompatibledatatypeforexplicittypeconversion
publicclassTypecast3
{
publicstaticvoidmain(String[]args)
{
Stringprice=“34”;
intnum=Integer.parseInt(price);
System.out.println(num);
}
}
Dr. Kuppusamy P

19. Chartointegerconversion
//incompatibledatatype
publicclassTypecast3
{
publicstaticvoidmain(String[]args)
{
charch=“c”;
intnum=88;
ch=num;
System.out.println(num);
}
}
Dr. Kuppusamy P

20. Typeconversion
Dr. Kuppusamy P

21. References
Dr. Kuppusamy P
Herbert Schildt, “Java: The Complete Reference”, McGraw-Hill Education, Tenth edition,
2017.