If-Else-If

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Why Use Else If?

In many real-world scenarios, a program must choose between several possible outcomes, not just true or false.
Using only if and else becomes inefficient because:

• Some conditions must be checked only if previous ones fail
• Writing multiple isolated if statements can create unnecessary checks
• The code becomes harder to read and maintain

The if–else-if ladder provides an elegant solution.
It lets the program evaluate conditions in sequence, and as soon as one becomes true, its block runs and the rest are ignored — improving clarity and efficiency.

Syntax

if (condition1) {
    // executes if condition1 is true
} else if (condition2) {
    // executes if condition2 is true
} else if (condition3) {
    // executes if condition3 is true
} else {
    // executes if all conditions are false
}

How it works

• Start with the first condition
• Move downward only if the current condition is false
• At the first true, the corresponding block executes
• The ladder ends immediately (remaining conditions are skipped)

This structure is ideal for ordered, priority-based decisions.

Example – Finding the Greatest of Three Numbers

public class Demo {
    public static void main(String[] args) {
        int x = 8;
        int y = 7;
        int z = 9;

        if (x > y && x > z) {
            System.out.println(x);
        } else if (y > z) {
            System.out.println(y);
        } else {
            System.out.println(z);
        }
    }
}

Output:

9

Flow Explanation

Let’s analyze the decision process step by step.

1. Check if x is greater than both y and z.

   • If this is true, x is the greatest → print x.
   • If false, move to the next condition.

2. Check if y is greater than z.

   • If true → print y.

3. Else (final option)

   • If neither of the above is true, then z must be the greatest → print z.

This ensures only one value is printed, and the logic is clear and predictable.

Why This Works Well

The if–else-if ladder naturally fits cases where:

• Only one outcome must be selected
• Conditions are mutually exclusive (cannot be true simultaneously)
• Decisions follow a clear order or priority

Examples include:

• Grading systems (A, B, C, D, F)
• Menu selections
• Range checking (e.g., temperature ranges)
• Category classification

Key Notes

• Execution stops at the first true condition — later conditions are ignored.
• The final else block is optional but helpful for handling unexpected values.
• Avoid writing unrelated conditions in one ladder; the chain should represent a logical progression.
• Helps keep code clean, structured, and easy for others to understand.

Written By: Shiva Srivastava