The document presents course material for Module 1 of Java Programming focusing on decision statements, including if statements, if-else branching, switch statements, and conditional operators. Key learning outcomes include understanding and applying various decision-making statements in Java for program logic. The content covers syntax and control flow for each statement type, along with examples and knowledge checks to reinforce learning.

1. SRI KRISHNA COLLEGE OF ENGINEERING AND TECHNOLOGY
Kuniamuthur, Coimbatore, Tamilnadu, India
An Autonomous Institution, Affiliated to Anna University,
Accredited by NAAC with “A” Grade & Accredited by NBA (CSE, ECE, IT, MECH ,EEE, CIVIL& MCT)
COURSE MATERIAL
Course : 22AD201 – Java Programming
Module : 1
Topic : Decision Statements
www.skcet.ac.in

2. www.skcet.ac.in
Module 1:
1.2. Decision Statements - if Statements, if-else Branching, switch Statements,
Conditional Operator
22AD201 Java Programming – Module 1
Text Book:
Herbert Schildt, “Java: The Complete Reference”, 9th edition, Tata McGraw Hill, 2014.
Web Resources:
https://www.ktbyte.com/java-tutorial/book/if-statements

3. Session Outcome
At the end of this session, you will be able to:
❖ Understand the various decision making statements in
java.
❖ Use the decision making statements in java to build logic
in programs.
❖ Choose appropriate decision statements as required by
particular problems.

4. ❖ if statements (one-way)
❖ if-else statements (two-way)
❖ nested if statements
❖ if-else statements (multi-way)
❖ switch statements
❖ conditional expressions
Types of Selection / Decision Statements

5. if statement executes an action if and only if the condition is true.
Syntax:
Example:
if statement in Java
if(boolean - expression)
{
statements(s);
}

6. Control Flow:
if statement in Java

7. if-else statement decides/chooses one of the two execution paths
based on whether the condition is true or false.
Syntax:
if-else statement in Java
if(boolean - expression)
{
statements(s) for the true-case;
}
else
{
statements(s) for the false-case;
}

8. Example:
Knowledge check:
What will be the output of the following code if number = 34?
if-else statement in Java

9. Control Flow:
if-else statement in Java

10. if statement may be included inside another if statement to create a
nested if.
Example:
❖ There is no limit to the depth of nesting of if statements.
Nested if statement in Java

11. Knowledge check:
With which if statement (first or second), is the else statement
associated?
if-else statement in Java
if (i > k)
{
if (j > k)
System.out.println("i and j are
greater than k");
else
System.out.println("i is less than or
equal to k");
}

12. Syntax:
Multi way if-else statements in Java
if(boolean - expression 1)
{
statements(s) to be executed if expression 1 is true;
}
else if (boolean - expression 2)
{
statements(s) to be executed if expression 1 is false & expression
2 is true ;
}
..
.
.
else
{
statements(s) to be executed if all above expressions are false;
}

13. Example:
Multi way if-else statements in Java

14. Control Flow:
Multi way if-else statements in Java

15. switch statement executes statements based on the value of a
variable or expression.
→ switch expression is evaluated
→ output of the switch expression is compared with all the case values.
→ Statements belonging to the case, for which, the switch expression is
equal to the case value, is executed.
→ If the switch expression does not match with any of the case values,
the statements under default are executed.
switch statements in Java

16. Syntax:
switch statements in Java
switch(expression)
{
case value1:
Statement(s) to be executed if (expression=value1);
break;
case value2:
Statement(s) to be executed if (expression=value2);
break;
case value3:
Statement(s) to be executed if (expression=value3);
break;
……..
default:
Statement(s) to be executed if expression did not match any of the
case values;
}

17. Example:
switch statements in Java
int day;
……
switch(day)
{
case 0:
System.out.println(“Sunday”);
break;
case 1:
System.out.println(“Monday”);
break;
……
default:
System.out.println(“Entered value is greater than 6”);
}

18. Knowledge check:
What will be the output of the following code?
i) if day=5 ii) if day=2 iii)if
day=0
if-else statement in Java

19. Control Flow:
switch statements in Java

20. ❖ The switch-expression must yield a value of char, byte, short, int,
or String type and must always be enclosed in parentheses.
❖ The case values, value1, . . ., upto value N must have the same data
type as the value of the switch- expression.
❖ value1, . . ., and value N are constant expressions, meaning that they
cannot contain variables, such as 1 + x.
❖ When the value in a case statement matches the value of the switch-
expression, the statements starting from this case are executed until
either a break statement or the end of the switch statement is
reached.
❖ The default case, which is optional, can be used to perform actions
when none of the specified cases matches the switch-expression.
❖ The keyword break is optional. The break statement immediately
ends the switch statement.
switch statements in Java - Rules

21. Also called as ternary operator. It is similar to the working of if-else.
Syntax:
Example:
Conditional expressions in Java
boolean - expression ? expression 1 : expression 2;