Unit-1/05 Type Casting – if-else/switch
Type Casting in Java
Type casting is the process of converting one data type into another. It is categorized into:
1. Implicit Type Casting (Widening Conversion): Converting a smaller data type into
a larger one automatically. Example: int to double.
2. Explicit Type Casting (Narrowing Conversion): Converting a larger data type into
a smaller one manually using (dataType). Example: double to int.
Program for Type Casting in Java
class TypeCastingExample {
public static void main(String[] args) {
// Implicit Type Casting (Widening)
int num = 100;
double doubleNum = num; // int to double conversion
System.out.println("Implicit Type Casting:");
System.out.println("Integer value: " + num);
System.out.println("Converted to double: " +
doubleNum);
// Explicit Type Casting (Narrowing)
double pi = 3.14159;
int intPi = (int) pi; // double to int conversion
System.out.println("\nExplicit Type Casting:");
System.out.println("Double value: " + pi);
System.out.println("Converted to integer: " + intPi);
}
}
Output
Implicit Type Casting:
Integer value: 100
Converted to double: 100.0
Explicit Type Casting:
Double value: 3.14159
Converted to integer: 3
Part-05
Unit-1/05 Type Casting – if-else/switch
Decision Statements in Java
Decision statements control the flow of execution based on conditions.
1. if Statement: Executes a block of code if the condition is true.
2. if-else Statement: Executes one block if the condition is true, otherwise executes
another block.
3. else-if Ladder: Used when multiple conditions need to be checked sequentially.
4. switch Statement: Used when there are multiple possible values for a variable,
replacing multiple if-else statements.
if Statement Example
class IfExample {
public static void main(String[] args) {
int num = 10;
if (num > 0) {
System.out.println("The number is positive.");
}
}
}
Output
The number is positive.
if-else Statement Example
class IfElseExample {
public static void main(String[] args) {
int num = -5;
if (num > 0) {
System.out.println("The number is positive.");
} else {
System.out.println("The number is negative or zero.");
}
}
}
Output
The number is negative or zero.
Part-05
Unit-1/05 Type Casting – if-else/switch
else-if Ladder Example
class ElseIfExample {
public static void main(String[] args) {
int marks = 85;
if (marks >= 90) {
System.out.println("Grade: A+");
} else if (marks >= 80) {
System.out.println("Grade: A");
} else if (marks >= 70) {
System.out.println("Grade: B");
} else if (marks >= 60) {
System.out.println("Grade: C");
} else {
System.out.println("Grade: F");
}
}
}
Output
Grade: A
switch Statement Example
import java.util.Scanner;
class SwitchExample {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.print("Enter a day number (1-7): ");
int day = sc.nextInt();
switch (day) {
case 1:
System.out.println("Monday");
break;
case 2:
System.out.println("Tuesday");
break;
case 3:
System.out.println("Wednesday");
break;
case 4:
System.out.println("Thursday");
break;
case 5:
System.out.println("Friday");
Part-05
Unit-1/05 Type Casting – if-else/switch
break;
case 6:
System.out.println("Saturday");
break;
case 7:
System.out.println("Sunday");
break;
default:
System.out.println("Invalid day number.");
}
sc.close();
}
}
Example Input & Output:
Enter a day number (1-7): 3
Wednesday
**Run program again
Enter a day number (1-7): 8
Invalid day number.
Part-05
