Nested conditions in Rust - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to check if a number is positive.

Rust

let num = 5;
if num [1] 0 {
    println!("Positive number");
}

Drag options to blanks, or click blank then click option'

A<

B>

C==

D<=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' instead of '>' will check for negative numbers.

Using '==' will only check if the number is zero.

The condition num > 0 checks if the number is positive.

2fill in blank

medium

Complete the code to check if a number is between 1 and 10 (inclusive).

Rust

let num = 7;
if num >= 1 && num [1] 10 {
    println!("Number is between 1 and 10");
}

Drag options to blanks, or click blank then click option'

A<=

B>

C==

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' excludes 10 from the range.

Using '>' or '==' does not check the upper bound correctly.

The condition num <= 10 ensures the number is at most 10.

3fill in blank

hard

Fix the error in the nested condition to print "Valid" if x is positive and less than 100.

Rust

let x = 50;
if x > 0 {
    if x [1] 100 {
        println!("Valid");
    }
}

Drag options to blanks, or click blank then click option'

A>=

B<=

C<

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<=' includes 100, which is not intended.

Using '>=' or '==' will not check the correct range.

The inner condition x < 100 checks if x is less than 100.

4fill in blank

hard

Fill both blanks to create a nested condition that prints "In range" if y is between 10 and 20 (exclusive).

Rust

let y = 15;
if y [1] 10 {
    if y [2] 20 {
        println!("In range");
    }
}

Drag options to blanks, or click blank then click option'

A>

B>=

C<

D<=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '>=' or '<=' includes the boundary values.

Mixing up the operators will cause incorrect range checks.

The conditions y > 10 and y < 20 check if y is strictly between 10 and 20.

5fill in blank

hard

Fill all three blanks to create a nested condition that prints "Valid score" if score is between 50 and 100 (inclusive) and is even.

Rust

let score = 80;
if score [1] 50 {
    if score [2] 100 {
        if score % 2 [3] 0 {
            println!("Valid score");
        }
    }
}

Drag options to blanks, or click blank then click option'

A>=

B<=

C==

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '>' or '<' excludes boundary values.

Using '!=' instead of '==' for even check causes wrong results.

The conditions check if score is at least 50, at most 100, and even (remainder 0 when divided by 2).

Practice

1.

What does nested conditions mean in Rust?

Choose the best description.

easy

A. Writing conditions without any if statements.

B. Using only one condition without any others.

C. Checking one condition inside another condition.

D. Ignoring conditions and running all code blocks.

Solution

1. Step 1: Understand the meaning of nested conditions

   Nested conditions mean putting one if or else if inside another to check multiple steps.

2. Step 2: Compare options with definition

   Only Checking one condition inside another condition. correctly describes checking one condition inside another.

3. Final Answer:

   Checking one condition inside another condition. -> Option C

4. Quick Check:

   Nested conditions = one condition inside another [OK]

Hint: Nested means inside another condition [OK]

Common Mistakes:

• Thinking nested means only one condition
• Confusing nested with multiple separate conditions
• Ignoring the use of if inside another if

2.

Which of the following is the correct syntax for nested if conditions in Rust?

fn main() {
    let x = 10;
    if x > 5 {
        if x < 15 {
            println!("x is between 6 and 14");
        }
    }
}

easy

A. The code shown above is correct.

B. You must use else if instead of nested if.

C. Rust does not allow nested if statements.

D. You need to add semicolons after if conditions.

Solution

1. Step 1: Check Rust syntax rules for nested if

   Rust allows if inside another if block without semicolons after conditions.

2. Step 2: Verify the given code

   The code uses nested if correctly and prints the message if both conditions are true.

3. Final Answer:

   The code shown above is correct. -> Option A

4. Quick Check:

   Nested if syntax correct = true [OK]

Hint: Nested if blocks need braces, no semicolon after conditions [OK]

Common Mistakes:

• Adding semicolons after if conditions
• Thinking else if must replace nested if
• Believing Rust disallows nested if

3.

What will be the output of this Rust code?

fn main() {
    let num = 8;
    if num > 5 {
        if num < 10 {
            println!("A");
        } else {
            println!("B");
        }
    } else {
        println!("C");
    }
}

medium

A. B

B. A

C. C

D. No output

Solution

1. Step 1: Check outer if condition

   Variable num is 8, which is greater than 5, so enter the first if block.

2. Step 2: Check inner if condition

   Inside, check if 8 is less than 10, which is true, so print "A".

3. Final Answer:

   A -> Option B

4. Quick Check:

   8 > 5 and 8 < 10 = "A" [OK]

Hint: Follow conditions step-by-step inside nested blocks [OK]

Common Mistakes:

• Ignoring inner if and printing wrong output
• Confusing else placement
• Assuming no output if conditions are true

4.

Find the error in this nested condition Rust code:

fn main() {
    let x = 3;
    if x > 0
        if x < 5 {
            println!("x is between 1 and 4");
        }
}

medium

A. The println! macro is used wrongly.

B. Incorrect comparison operators used.

C. Variable x is not declared.

D. Missing braces for the outer if block.

Solution

1. Step 1: Check syntax of outer if

   The outer if lacks braces, so the inner if is not properly nested.

2. Step 2: Understand Rust's block requirements

   Rust requires braces to group nested blocks clearly; missing braces cause syntax errors.

3. Final Answer:

   Missing braces for the outer if block. -> Option D

4. Quick Check:

   Braces needed for nested if blocks [OK]

Hint: Always use braces {} for nested if blocks [OK]

Common Mistakes:

• Skipping braces for nested if
• Misreading comparison operators
• Assuming println! usage is wrong

5.

Write a nested condition in Rust that prints:

• "Small and even" if a number is less than 10 and even,
• "Small and odd" if less than 10 and odd,
• "Large number" if 10 or more.

Which code snippet correctly implements this?

fn main() {
    let n = 8;
    // Choose the correct nested condition
}

hard

A. if n < 10 {
if n % 2 == 0 {
println!("Small and even");
} else {
println!("Small and odd");
}
} else {
println!("Large number");
}

B. if n % 2 == 0 {
if n < 10 {
println!("Small and even");
} else {
println!("Large number");
}
} else {
println!("Small and odd");
}

C. if n < 10 && n % 2 == 0 {
println!("Small and even");
} else if n < 10 {
println!("Small and odd");
} else {
println!("Large number");
}

D. if n < 10 {
println!("Small and even");
} else if n % 2 == 0 {
println!("Large number");
} else {
println!("Small and odd");
}

Solution

1. Step 1: Check outer condition for number size

   if n < 10 { if n % 2 == 0 { println!("Small and even"); } else { println!("Small and odd"); } } else { println!("Large number"); } first checks if n < 10, then inside checks even or odd.

2. Step 2: Verify inner conditions and outputs

   If even, prints "Small and even"; else prints "Small and odd". If not less than 10, prints "Large number".

3. Final Answer:

   Option A correctly implements the nested conditions as described. -> Option A

4. Quick Check:

   Outer size check, inner even/odd check = if n < 10 { if n % 2 == 0 { println!("Small and even"); } else { println!("Small and odd"); } } else { println!("Large number"); } [OK]

Hint: Check outer condition first, then inner even/odd [OK]

Common Mistakes:

• Checking even before size
• Mixing up print messages
• Using flat conditions instead of nested