Nested conditional execution in C Sharp (C#) - Mini Project: Build & Apply

Nested Conditional Execution

📖 Scenario: You are creating a simple program to help a coffee shop decide the price of a coffee order based on the size and whether the customer wants extra syrup.

🎯 Goal: Build a program that uses nested if statements to determine the final price of a coffee order based on size and syrup option.

📋 What You'll Learn

Create a variable size with the exact value "medium".

Create a variable extraSyrup with the exact value true.

Use nested if statements to set the price variable based on size and extraSyrup.

Print the final price using Console.WriteLine.

💡 Why This Matters

🌍 Real World

Coffee shops and many other businesses use nested conditions to calculate prices based on options customers choose.

💼 Career

Understanding nested conditional execution is essential for programming tasks like pricing, form validation, and decision-making in software.

1

Create initial variables

Create a string variable called size and set it to "medium". Create a boolean variable called extraSyrup and set it to true.

C Sharp (C#)

// Your code here

Hint

Use string size = "medium"; and bool extraSyrup = true; to create the variables.

2

Add price variable

Create a double variable called price and set it to 0.

C Sharp (C#)

string size = "medium";
bool extraSyrup = true;
// Your code here

Hint

Use double price = 0; to create the price variable.

3

Use nested if statements to set price

Use nested if statements with size and extraSyrup to set price as follows:
- If size is "small", price is 2.0, add 0.5 if extraSyrup is true.
- If size is "medium", price is 3.0, add 0.5 if extraSyrup is true.
- If size is "large", price is 4.0, add 0.5 if extraSyrup is true.

C Sharp (C#)

string size = "medium";
bool extraSyrup = true;
double price = 0;
// Your code here

Hint

Use nested if inside each size check to add 0.5 if extraSyrup is true.

4

Print the final price

Use Console.WriteLine to print the text "Final price: " followed by the price variable.

C Sharp (C#)

string size = "medium";
bool extraSyrup = true;
double price = 0;

if (size == "small")
{
    price = 2.0;
    if (extraSyrup)
    {
        price += 0.5;
    }
}
else if (size == "medium")
{
    price = 3.0;
    if (extraSyrup)
    {
        price += 0.5;
    }
}
else if (size == "large")
{
    price = 4.0;
    if (extraSyrup)
    {
        price += 0.5;
    }
}
// Your code here

Hint

Use Console.WriteLine("Final price: " + price); to print the result.

Practice

1. What does nested conditional execution mean in C#?

easy

A. Running code without any conditions

B. Checking one condition inside another condition

C. Using only one if statement without else

D. Writing multiple if statements separately

Solution

1. Step 1: Understand the meaning of nested conditions

   Nested conditional execution means putting one if or else if statement inside another to check multiple conditions step-by-step.

2. Step 2: Compare options with definition

   Only Checking one condition inside another condition describes checking one condition inside another, which matches nested conditional execution.

3. Final Answer:

   Checking one condition inside another condition -> Option B

4. Quick Check:

   Nested condition = condition inside condition [OK]

Hint: Think of conditions inside conditions like boxes inside boxes [OK]

Common Mistakes:

• Confusing nested with multiple separate if statements
• Thinking nested means no else parts
• Believing nested means no conditions at all

2. Which of the following is the correct syntax for nested if statements in C#?

easy

A. if (x > 0) { if (x < 10) { Console.WriteLine("Inside"); } }

B. if x > 0 then if x < 10 then Console.WriteLine("Inside")

C. if (x > 0 if (x < 10) Console.WriteLine("Inside") else Console.WriteLine("Outside");

D. if (x > 0) { Console.WriteLine("Inside"); } else if (x < 10) { Console.WriteLine("Inside"); }

Solution

1. Step 1: Review C# nested if syntax

   Nested if means an if statement inside another if's braces, both with parentheses and braces.

2. Step 2: Check each option

   if (x > 0) { if (x < 10) { Console.WriteLine("Inside"); } } correctly uses braces and parentheses for nested if. if x > 0 then if x < 10 then Console.WriteLine("Inside") uses wrong syntax (no parentheses). if (x > 0 if (x < 10) Console.WriteLine("Inside") else Console.WriteLine("Outside"); misses braces and has syntax error (missing closing parenthesis). if (x > 0) { Console.WriteLine("Inside"); } else if (x < 10) { Console.WriteLine("Inside"); } is separate if-else, not nested.

3. Final Answer:

   if (x > 0) { if (x < 10) { Console.WriteLine("Inside"); } } -> Option A

4. Quick Check:

   Nested if needs braces and parentheses [OK]

Hint: Look for braces inside braces with proper parentheses [OK]

Common Mistakes:

• Omitting parentheses around conditions
• Missing braces for nested blocks
• Confusing else placement in nested if

3. What will be the output of this C# code?

int x = 5;
if (x > 0) {
  if (x < 10) {
    Console.WriteLine("A");
  } else {
    Console.WriteLine("B");
  }
} else {
  Console.WriteLine("C");
}

medium

A. A

B. B

C. C

D. No output

Solution

1. Step 1: Check outer if condition

   x = 5, so x > 0 is true, enter first if block.

2. Step 2: Check inner if condition

   Inside first if, check if x < 10. Since 5 < 10 is true, print "A".

3. Final Answer:

   A -> Option A

4. Quick Check:

   x=5 >0 and <10 prints A [OK]

Hint: Follow conditions step-by-step inside each if [OK]

Common Mistakes:

• Ignoring inner if and printing else block
• Confusing else belonging to which if
• Assuming no output if conditions are true

4. Find the error in this nested conditional code:

int y = 8;
if (y > 5)
  if (y < 10)
    Console.WriteLine("Inside");
  else
    Console.WriteLine("Outside");

medium

A. Missing braces causing else to pair with wrong if

B. Syntax error: missing semicolon after if

C. Variable y is not declared

D. No error, code runs fine

Solution

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

   Without braces, else pairs with nearest if (the inner one). This is correct C# syntax.

2. Step 2: Check for errors

   The code compiles and runs fine with no syntax error, undefined variables, or crashes. Braces are recommended for clarity but not required here.

3. Final Answer:

   No error, code runs fine -> Option D

4. Quick Check:

   Code runs correctly without braces [OK]

Hint: Use braces to clearly group if-else blocks [OK]

Common Mistakes:

• Thinking semicolon needed after if
• Assuming else pairs with outer if
• Ignoring braces importance

5. You want to write a nested conditional in C# that prints "Small Positive" if a number is greater than 0 and less than 10, "Large Positive" if greater or equal to 10, and "Non-positive" otherwise. Which code correctly implements this?

hard

A. if (num < 10) { if (num > 0) { Console.WriteLine("Non-positive"); } else { Console.WriteLine("Small Positive"); } } else { Console.WriteLine("Large Positive"); }

B. if (num > 0 && num < 10) { Console.WriteLine("Small Positive"); } else if (num >= 10) { Console.WriteLine("Large Positive"); } else { Console.WriteLine("Non-positive"); }

C. if (num > 0) { if (num < 10) { Console.WriteLine("Small Positive"); } else { Console.WriteLine("Large Positive"); } } else { Console.WriteLine("Non-positive"); }

D. if (num > 0) { Console.WriteLine("Small Positive"); } else if (num < 10) { Console.WriteLine("Large Positive"); } else { Console.WriteLine("Non-positive"); }

Solution

1. Step 1: Understand conditions to check

   We want to check if num > 0 and num < 10 for "Small Positive", else if num >= 10 for "Large Positive", else "Non-positive".

2. Step 2: Check nested if logic

   if (num > 0) { if (num < 10) { Console.WriteLine("Small Positive"); } else { Console.WriteLine("Large Positive"); } } else { Console.WriteLine("Non-positive"); } correctly nests the second condition inside the first if (num > 0), checking num < 10 inside it, else prints "Large Positive". Else prints "Non-positive".

3. Final Answer:

   if (num > 0) { if (num < 10) { Console.WriteLine("Small Positive"); } else { Console.WriteLine("Large Positive"); } } else { Console.WriteLine("Non-positive"); } -> Option C

4. Quick Check:

   Nested if matches conditions exactly [OK]

Hint: Nest second condition inside first to separate ranges clearly [OK]

Common Mistakes:

• Using && instead of nested if for this logic
• Swapping else blocks incorrectly
• Not covering all cases properly