Else–if ladder in Java - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of Else–if Ladder with Multiple Conditions

What is the output of the following Java code?

Java

public class Test {
    public static void main(String[] args) {
        int score = 75;
        if (score >= 90) {
            System.out.println("Grade A");
        } else if (score >= 80) {
            System.out.println("Grade B");
        } else if (score >= 70) {
            System.out.println("Grade C");
        } else {
            System.out.println("Grade F");
        }
    }
}

A Grade C

B Grade B

C Grade A

D Grade F

💡 Hint

Check which condition the score 75 satisfies first in the else-if ladder.

The score 75 is not >= 90 or >= 80, but it is >= 70, so the else-if block for Grade C runs.

❓ Predict Output

intermediate

Output When No Conditions Match in Else–if Ladder

What will be printed when the input value is 45 in this Java program?

Java

public class Test {
    public static void main(String[] args) {
        int value = 45;
        if (value > 100) {
            System.out.println("High");
        } else if (value > 50) {
            System.out.println("Medium");
        } else if (value > 60) {
            System.out.println("Above Average");
        } else {
            System.out.println("Low");
        }
    }
}

A High

B Medium

C Low

D Above Average

💡 Hint

Check all conditions carefully and see which one matches 45.

45 is not greater than 100, 50, or 60, so the else block runs printing "Low".

🔧 Debug

advanced

Identify the Error in Else–if Ladder Syntax

What error does this Java code produce?

Java

public class Test {
    public static void main(String[] args) {
        int num = 10;
        if (num > 0) {
            System.out.println("Positive");
        } else if (num == 0) {
            System.out.println("Zero");
        } else {
            System.out.println("Negative");
        }
    }
}

A RuntimeException: Null pointer exception

B SyntaxError: Missing parentheses in else-if condition

C No error, prints "Positive"

D Logical error: prints wrong output

💡 Hint

Check the syntax of the else-if statement carefully.

In Java, else-if conditions must be enclosed in parentheses. Missing parentheses cause a syntax error.

🚀 Application

advanced

Determine the Final Value After Else–if Ladder Execution

What is the value of variable 'result' after running this Java code?

Java

public class Test {
    public static void main(String[] args) {
        int x = 15;
        String result;
        if (x < 10) {
            result = "Less";
        } else if (x < 20) {
            result = "Between";
        } else if (x < 30) {
            result = "More";
        } else {
            result = "Unknown";
        }
        System.out.println(result);
    }
}

A Between

B Less

C More

D Unknown

💡 Hint

Check which condition the value 15 satisfies first.

15 is not less than 10 but is less than 20, so 'Between' is assigned and printed.

🧠 Conceptual

expert

Understanding Else–if Ladder Execution Flow

Consider the following Java code snippet. Which statement best describes the execution flow when x = 25?

Java

int x = 25;
if (x > 30) {
    System.out.println("Above 30");
} else if (x > 20) {
    System.out.println("Above 20");
} else if (x > 10) {
    System.out.println("Above 10");
} else {
    System.out.println("10 or below");
}

A Prints "10 or below" because none of the conditions match

B Prints "Above 30" because it checks all conditions

C Prints "Above 10" because it matches the last else-if

D Prints "Above 20" and skips remaining else-if blocks

💡 Hint

Remember that else-if ladder stops checking after the first true condition.

Since x=25 is not >30 but is >20, it prints "Above 20" and skips the rest.

Practice

1. What does an else-if ladder in Java help you do?

easy

A. Run all conditions regardless of their truth

B. Check multiple conditions one by one until one is true

C. Only check the first condition and ignore others

D. Skip conditions and run else block always

Solution

1. Step 1: Understand the purpose of else-if ladder

   An else-if ladder lets you test several conditions in order, stopping at the first true one.

2. Step 2: Compare options with this behavior

   Only Check multiple conditions one by one until one is true correctly describes checking conditions one by one until one is true.

3. Final Answer:

   Check multiple conditions one by one until one is true -> Option B

4. Quick Check:

   Else-if ladder = check conditions one by one [OK]

Hint: Else-if ladder stops at first true condition [OK]

Common Mistakes:

• Thinking all conditions run regardless
• Confusing else-if with separate if statements
• Believing else runs before conditions

2. Which of the following is the correct syntax for an else-if ladder in Java?

easy

A. if(condition) { } else if condition { } else { }

B. if(condition) { } else(condition) { } else { }

C. if condition { } else if(condition) { } else { }

D. if(condition) { } else if(condition) { } else { }

Solution

1. Step 1: Recall Java syntax for else-if ladder

   Java requires parentheses around conditions and braces for blocks: if(condition) { } else if(condition) { } else { }

2. Step 2: Check each option for syntax errors

   Only if(condition) { } else if(condition) { } else { } uses correct parentheses and braces. Others miss parentheses or use wrong keywords.

3. Final Answer:

   if(condition) { } else if(condition) { } else { } -> Option D

4. Quick Check:

   Correct else-if syntax = if(condition) { } else if(condition) { } else { } [OK]

Hint: Use parentheses for conditions and braces for blocks [OK]

Common Mistakes:

• Omitting parentheses around conditions
• Writing else with a condition (should be else if)
• Missing braces for code blocks

3. What will be the output of this Java code?

int score = 75;
if(score >= 90) {
  System.out.println("Grade A");
} else if(score >= 80) {
  System.out.println("Grade B");
} else if(score >= 70) {
  System.out.println("Grade C");
} else {
  System.out.println("Fail");
}

medium

A. Grade C

B. Grade B

C. Fail

D. Grade A

Solution

1. Step 1: Check conditions in order with score = 75

   score >= 90? No (75 < 90). Next condition.

2. Step 2: Check next conditions

   score >= 80? No (75 < 80). Next condition.
   score >= 70? Yes (75 >= 70). So print "Grade C" and skip else.

3. Final Answer:

   Grade C -> Option A

4. Quick Check:

   75 is between 70 and 79 = Grade C [OK]

Hint: Check conditions top to bottom, first true runs [OK]

Common Mistakes:

• Choosing Grade B or A by mistake
• Ignoring else-if order
• Assuming else runs even if condition true

4. Find the error in this else-if ladder code snippet:

int num = 10;
if(num > 10) {
  System.out.println("Greater than 10");
} else if num == 10 {
  System.out.println("Equal to 10");
} else {
  System.out.println("Less than 10");
}

medium

A. Missing semicolon after print statements

B. Using else instead of else-if

C. Missing parentheses around condition in else-if

D. No error, code is correct

Solution

1. Step 1: Check syntax of else-if condition

   In Java, conditions must be inside parentheses. Here, else if num == 10 lacks parentheses.

2. Step 2: Verify other parts

   Print statements have semicolons, else-if is used correctly, so no other errors.

3. Final Answer:

   Missing parentheses around condition in else-if -> Option C

4. Quick Check:

   Conditions need parentheses [OK]

Hint: Always put conditions inside parentheses [OK]

Common Mistakes:

• Forgetting parentheses in else-if
• Confusing else and else-if syntax
• Missing semicolons (not the issue here)

5. You want to write a program that assigns a letter grade based on score:
- 90 and above: A
- 80 to 89: B
- 70 to 79: C
- 60 to 69: D
- Below 60: F
Which else-if ladder correctly implements this?

hard

A. if(score >= 90) { grade = 'A'; } else if(score >= 80) { grade = 'B'; } else if(score >= 70) { grade = 'C'; } else if(score >= 60) { grade = 'D'; } else { grade = 'F'; }

B. if(score > 90) { grade = 'A'; } else if(score > 80) { grade = 'B'; } else if(score > 70) { grade = 'C'; } else if(score > 60) { grade = 'D'; } else { grade = 'F'; }

C. if(score >= 90) { grade = 'A'; } else if(score > 80) { grade = 'B'; } else if(score >= 70) { grade = 'C'; } else if(score >= 60) { grade = 'D'; } else { grade = 'F'; }

D. if(score >= 90) { grade = 'A'; } else if(score >= 80) { grade = 'B'; } else if(score >= 70) { grade = 'C'; } else if(score > 60) { grade = 'D'; } else { grade = 'F'; }

Solution

1. Step 1: Understand the grade ranges and conditions

   Grades are assigned for score ranges including boundaries: 90+, 80-89, 70-79, 60-69, below 60.

2. Step 2: Check each option's condition operators

   if(score >= 90) { grade = 'A'; } else if(score >= 80) { grade = 'B'; } else if(score >= 70) { grade = 'C'; } else if(score >= 60) { grade = 'D'; } else { grade = 'F'; } uses >= for lower bounds correctly. The other options use > in some places, which excludes boundary values (like 80 or 60).

3. Final Answer:

   if(score >= 90) { grade = 'A'; } else if(score >= 80) { grade = 'B'; } else if(score >= 70) { grade = 'C'; } else if(score >= 60) { grade = 'D'; } else { grade = 'F'; } -> Option A

4. Quick Check:

   Use >= for inclusive ranges [OK]

Hint: Use >= for inclusive score ranges [OK]

Common Mistakes:

• Using > instead of >= excludes boundary scores
• Overlapping or missing ranges
• Incorrect else placement