Java if-else-if ladder with Examples

The Java if-else-if ladder is used to evaluate multiple conditions sequentially. It allows a program to check several conditions and execute the block of code associated with the first true condition. If none of the conditions are true, an optional else block can execute as a fallback.

Example: The below example demonstrates a straightforward if-else-if ladder structure. It evaluates a number and prints the corresponding message based on the condition.

// Java program to demonstrate 
// a simple if-else-if ladder
class GFG {
  
    public static void main(String[] args) {
      
        int i = 20;

        // if-else-if ladder to check the value of i
        if (i == 10)
            System.out.println("i is 10");
        else if (i == 20)
            System.out.println("i is 20");
        else
            System.out.println("i is neither 10 nor 20");
    }
}

i is 20

Dry-Running Above Example

1. Program starts.
2. i is initialized to 20.
3. The first if condition i == 10 is checked:
   1. It evaluates to false because i is 20.
4. The second else if condition i == 20 is checked:
   1. It evaluates to true because i is 20.
   2. 4.a) "i is 20" gets printed.
5. The else block is skipped since a condition was satisfied.
6. Program ends.

Syntax of if-else-if ladder:

if (condition)
statement 1;
else if (condition)
statement 2;
.
.
else
statement;

Working of the if-else-if ladder:  

1. Control falls into the if block.
2. The flow jumps to Condition 1.
3. Condition is tested. 
   
   1. If Condition yields true, go to Step 4.
   2. If Condition yields false, go to Step 5.
4. The present block is executed. Go to Step 7.
5. The flow jumps to Condition 2. 
   
   1. If Condition yields true, go to step 4.
   2. If Condition yields false, go to Step 6.
6. The flow jumps to Condition 3. 
   
   1. If Condition yields true, go to step 4.
   2. If Condition yields false, execute else block. 
      Go to Step 7.
7. Exit the if-else-if ladder.
   

Flowchart if-else-if ladder:

The above flowchart represents the working of an if-else-if ladder in a program. It evaluates conditions sequentially and executes the corresponding statement or the else block if none of the conditions are true.

Example 1:

// Java program to illustrate if-else-if ladder
import java.io.*;

class GFG {
  
    public static void main(String[] args) {
      
        // initializing expression
        int i = 20;

        // condition 1
        if (i == 10)
            System.out.println("i is 10\n");

        // condition 2
        else if (i == 15)
            System.out.println("i is 15\n");

        // condition 3
        else if (i == 20)
            System.out.println("i is 20\n");

        else
            System.out.println("i is not present\n");

        System.out.println("Outside if-else-if");
    }
}

i is 20

Outside if-else-if

Explanation: The above example demonstrates an if-else-if ladder to check the value of "i" against multiple conditions. It prints the matching condition's output or a default message.

Advantages of Java if-else-if Ladder

• Sequential Condition Checking: It allows multiple conditions to be evaluated in order by making it useful for handling a range of scenarios.
• Readability: It is easy to read and understand for simple decision-making logic.
• Fallback Mechanism: This provides an optional else block to handle cases where none of the conditions are met.
• Versatile: This can be used for both numerical and logical comparisons.
• Simpler Alternative: It is suitable for situations where using switch is not feasible, such as complex conditions.