Nested if statements in Java - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of nested if with multiple conditions

What is the output of the following Java code?

Java

public class Test {
    public static void main(String[] args) {
        int x = 10;
        int y = 20;
        if (x > 5) {
            if (y < 15) {
                System.out.println("A");
            } else {
                System.out.println("B");
            }
        } else {
            System.out.println("C");
        }
    }
}

A A

B No output

C C

D B

💡 Hint

Check the conditions inside each if block carefully.

The outer if checks if x > 5, which is true (10 > 5). Then the inner if checks if y < 15, which is false (20 < 15 is false). So it goes to the else block and prints "B".

❓ Predict Output

intermediate

Nested if with else-if ladder output

What will be printed when this Java code runs?

Java

public class Check {
    public static void main(String[] args) {
        int score = 75;
        if (score >= 90) {
            System.out.println("Excellent");
        } else {
            if (score >= 70) {
                System.out.println("Good");
            } else {
                System.out.println("Needs Improvement");
            }
        }
    }
}

A Excellent

B Good

C Needs Improvement

D No output

💡 Hint

Look at the score and compare with each condition.

Score is 75, which is not >= 90, so the first if fails. Then the nested if checks if score >= 70, which is true, so it prints "Good".

🔧 Debug

advanced

Identify the error in nested if syntax

What error will this Java code produce when compiled?

Java

public class ErrorTest {
    public static void main(String[] args) {
        int a = 5;
        if (a > 0)
            if (a < 10)
                System.out.println("Inside");
            else
                System.out.println("Outside");
    }
}

A No error, prints "Inside"

B Runtime error

C No error, prints "Outside"

D Syntax error: else without if

💡 Hint

Check how else is matched with if in nested statements without braces.

The else is matched with the nearest if, but indentation is misleading. Without braces, the else pairs with the inner if. The code compiles but the indentation suggests a logic error. However, no syntax error occurs. But since the question asks for error, the correct answer is no error. To fix this, braces are needed. But since only one option can be correct, the best fit is no error and prints "Inside".

❓ Predict Output

advanced

Output of nested if with boolean flags

What is the output of this Java program?

Java

public class Flags {
    public static void main(String[] args) {
        boolean isRaining = true;
        boolean haveUmbrella = false;
        if (isRaining) {
            if (haveUmbrella) {
                System.out.println("Go outside");
            } else {
                System.out.println("Stay inside");
            }
        } else {
            System.out.println("Enjoy the sun");
        }
    }
}

A Go outside

B Enjoy the sun

C Stay inside

D No output

💡 Hint

Check the values of both boolean variables and the nested conditions.

isRaining is true, so the outer if is true. Then haveUmbrella is false, so the inner else runs and prints "Stay inside".

❓ Predict Output

expert

Value of variable after nested if execution

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

Java

public class NestedIfTest {
    public static void main(String[] args) {
        int x = 8;
        int y = 12;
        String result = "";
        if (x > 5) {
            if (y > 10) {
                result = "A";
            } else if (y > 5) {
                result = "B";
            } else {
                result = "C";
            }
        } else {
            result = "D";
        }
        System.out.println(result);
    }
}

A A

B B

C D

D C

💡 Hint

Check each condition carefully and see which block runs.

x is 8, which is > 5, so outer if runs. y is 12, which is > 10, so first inner if runs and sets result to "A".

Practice

1. What does a nested if statement mean in Java?

easy

A. An if statement without any condition

B. An if statement with multiple conditions joined by ||

C. An if statement inside another if statement

D. An if statement that runs only once

Solution

1. Step 1: Understand the meaning of nested if

   A nested if means placing one if statement inside another to check conditions step-by-step.

2. Step 2: Compare options

   Only An if statement inside another if statement describes an if inside another if. Others describe different concepts.

3. Final Answer:

   An if statement inside another if statement -> Option C

4. Quick Check:

   Nested if = if inside if [OK]

Hint: Look for 'if inside if' meaning nested [OK]

Common Mistakes:

• Confusing nested if with multiple conditions in one if
• Thinking nested if runs only once
• Ignoring the inner if statement

2. Which of the following is the correct syntax for a nested if statement in Java?

easy

A. if (x > 0) if y > 0 { System.out.println("Both positive"); }

B. if (x > 0) { if (y > 0) { System.out.println("Both positive"); } }

C. if x > 0 { if y > 0 { System.out.println("Both positive"); } }

D. if (x > 0) { if (y > 0) System.out.println("Both positive") }

Solution

1. Step 1: Check Java syntax rules for if

   Java requires parentheses around conditions and braces for blocks.

2. Step 2: Validate each option

   if (x > 0) { if (y > 0) { System.out.println("Both positive"); } } uses correct parentheses and braces. if (x > 0) if y > 0 { System.out.println("Both positive"); } misses parentheses around y > 0. if x > 0 { if y > 0 { System.out.println("Both positive"); } } misses parentheses and braces. if (x > 0) { if (y > 0) System.out.println("Both positive") } misses semicolon after println.

3. Final Answer:

   if (x > 0) { if (y > 0) { System.out.println("Both positive"); } } -> Option B

4. Quick Check:

   Correct syntax = if (x > 0) { if (y > 0) { System.out.println("Both positive"); } } [OK]

Hint: Remember: conditions need parentheses, blocks need braces [OK]

Common Mistakes:

• Omitting parentheses around conditions
• Forgetting braces for nested blocks
• Missing semicolons after statements

3. What will be the output of this code?

int a = 5;
int b = 10;
if (a > 0) {
  if (b < 5) {
    System.out.println("Inside inner if");
  } else {
    System.out.println("Inside else of inner if");
  }
} else {
  System.out.println("Inside outer else");
}

medium

A. Inside else of inner if

B. Inside outer else

C. Inside inner if

D. No output

Solution

1. Step 1: Evaluate outer if condition

   a = 5, so a > 0 is true, enter outer if block.

2. Step 2: Evaluate inner if condition

   b = 10, b < 5 is false, so else block of inner if runs.

3. Final Answer:

   Inside else of inner if -> Option A

4. Quick Check:

   Outer if true, inner if false -> inner else [OK]

Hint: Check outer if first, then inner if conditions [OK]

Common Mistakes:

• Ignoring the else block of inner if
• Confusing outer else with inner else
• Assuming no output if inner if false

4. Find the error in this nested if code:

int x = 10;
if (x > 5)
  if (x < 20)
    System.out.println("x is between 5 and 20");
  else
    System.out.println("x is 5 or less");

medium

A. Missing braces causing else to pair with wrong if

B. Incorrect condition syntax

C. Missing semicolon after println

D. Variable x not declared

Solution

1. Step 1: Analyze if-else pairing without braces

   Without braces, else pairs with nearest if, here inner if.

2. Step 2: Understand the logic error

   Else prints "x is 5 or less" only if x >= 20, which is wrong logically.

3. Final Answer:

   Missing braces causing else to pair with wrong if -> Option A

4. Quick Check:

   Braces fix else pairing [OK]

Hint: Use braces to avoid else pairing mistakes [OK]

Common Mistakes:

• Assuming else pairs with outer if
• Ignoring braces importance
• Thinking syntax error instead of logic error

5. You want to write a nested if to check if a number is positive and even. Which code correctly does this?

hard

A. if (num > 0) { if (num % 2 = 0) { System.out.println("Positive even"); } }

B. if (num > 0 && num % 2 == 0) System.out.println("Positive even");

C. if (num > 0) if (num / 2 == 0) System.out.println("Positive even");

D. if (num > 0) { if (num % 2 == 0) { System.out.println("Positive even"); } }

Solution

1. Step 1: Check condition for positive number

   First if checks if num > 0, correct for positive check.

2. Step 2: Check condition for even number inside first if

   Inner if uses num % 2 == 0, correct for even check.

3. Final Answer:

   if (num > 0) { if (num % 2 == 0) { System.out.println("Positive even"); } } -> Option D

4. Quick Check:

   Nested if with correct conditions = if (num > 0) { if (num % 2 == 0) { System.out.println("Positive even"); } } [OK]

Hint: Use % 2 == 0 to check even inside positive check [OK]

Common Mistakes:

• Using single = instead of == in condition
• Using division instead of modulo for even check
• Combining conditions without nesting