Java Conditional Statements
Java Conditional Statements
Java conditional statements are used to control the flow of execution in a program based on specific conditions. These conditions evaluate to either true or false. Conditional statements allow decision-making and execution of specific code blocks depending on whether the condition is met.
Here’s a detailed explanation of Java's primary conditional statements, with syntax and examples:
1. if Statement
The if statement checks a condition. When the condition evaluates as true, the code block inside the if statement is executed
if (condition) {
// Instructions to run if the condition is true
}
public class IfExample {
public static void main(String[] args) {
int number = 10;
if (number > 0) {
System.out.println("The number is positive.");
}
}
}
Explanation:
Here, the condition number > 0 is evaluated. Since 10 > 0 is true, the message "The number is positive." is displayed.
2. if-else Statement
The if-else statement provides an alternative path of execution if the condition evaluates to false.
if (condition) {
// Instructions or code to run if the condition is true
} else {
// Instructions or Code to execute if the condition is false
}
public class IfElseExample {
public static void main(String[] args) {
int number = -5;
if (number > 0) {
System.out.println("The number is positive.");
} else {
System.out.println("The number is not positive.");
}
}
}
Explanation:
If number > 0 is false (as in this case), the code in the else block executes, displaying "The number is not positive."
3. if-else-if Ladder
This allows checking multiple conditions in a sequential manner.
if (condition1) {
// Code if condition1 is true
} else if (condition2) {
// Code if condition2 is true
} else {
// CActions to perform if none of the conditions are met.
}
public class IfElseIfExample {
public static void main(String[] args) {
int marks = 75;
if (marks >= 90) {
System.out.println("Grade: A");
} else if (marks >= 75) {
System.out.println("Grade: B");
} else if (marks >= 50) {
System.out.println("Grade: C");
} else {
System.out.println("Grade: F");
}
}
}
Explanation:
The conditions are checked in order, and the first condition that evaluates to true determines which code block runs. Here, marks >= 75 is true, so "Grade: B" is printed.
4. switch Statement
A switch statement checks the value of a variable or expression and runs the corresponding case block.
switch (expression) {
case value1:
// Code to execute if expression == value1
break;
case value2:
// Code to execute if expression == value2
break;
// Additional cases
default:
// Instructions or code to execute if no case matches.
}
public class SwitchExample {
public static void main(String[] args) {
int day = 3;
switch (day) {
case 1:
System.out.println("Monday");
break;
case 2:
System.out.println("Tuesday");
break;
case 3:
System.out.println("Wednesday");
break;
default:
System.out.println("Invalid day");
}
}
}
Explanation:
The switch statement compares the variable day with each case. If it matches 3, it runs the related code and exits the switch
Key Points to Remember:
- Always use {} braces for blocks in if, else, and else if statements, even for single-line statements, to improve readability and avoid errors.
- switch is ideal for situations with multiple discrete options.
- Avoid forgetting the break statement in switch cases to prevent unintended fall-through behavior.
This detailed breakdown should give you a clear understanding of Java conditional statements!
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- 📌 #12 If else in Java
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