Part 4: Simple Nested If Statements

Nested if statements let you create different paths in your game. Let's look at a simple 2-level nested structure where your first choice determines what happens in your second choice.

What is a 2-Level Nested If?

A 2-level nested if has: - Level 1: Your first choice (which path to take) - Level 2: Different options based on your first choice

Simple 2-Level Example

Here's how to create different screens and choices based on your first decision:

void loop() {
  // Show start screen
  engine.display.clear();
  engine.display.drawBitmap(0, 0, KYWY_DISPLAY_WIDTH, KYWY_DISPLAY_HEIGHT, startScreen);
  drawInstructionText();
  engine.display.update();

  ButtonEvent choice = waitForInput();

  // LEVEL 1: First choice determines the path
  if (choice == Kywy::Events::KywyEvents::D_PAD_LEFT_PRESSED) {
    // PATH A: Forest path
    engine.display.clear();
    drawColoredScreen(0x07E0); // Green for forest
    drawBottomText("You enter a peaceful forest.\nLeft: Follow the stream\nRight: Climb the hill");
    engine.display.update();

    // LEVEL 2: Second choice depends on being in the forest
    choice = waitForInput();

    if (choice == Kywy::Events::KywyEvents::D_PAD_LEFT_PRESSED) {
      // Forest + Stream = Find treasure
      engine.display.clear();
      drawColoredScreen(0x07FF); // Cyan
      score += 20;
      drawBottomText("You follow the stream and find treasure!\n(+20 points)");
    } else if (choice == Kywy::Events::KywyEvents::D_PAD_RIGHT_PRESSED) {
      // Forest + Hill = Get lost
      engine.display.clear();
      drawColoredScreen(0xF800); // Red
      health -= 10;
      drawBottomText("You climb the hill but get lost!\n(-10 health)");
    }

  } else if (choice == Kywy::Events::KywyEvents::D_PAD_RIGHT_PRESSED) {
    // PATH B: Mountain path
    engine.display.clear();
    drawColoredScreen(0x2945); // Dark for mountain
    drawBottomText("You climb a steep mountain.\nLeft: Look for a cave\nRight: Cross the bridge");
    engine.display.update();

    // LEVEL 2: Second choice depends on being on the mountain
    choice = waitForInput();

    if (choice == Kywy::Events::KywyEvents::D_PAD_LEFT_PRESSED) {
      // Mountain + Cave = Find shelter
      engine.display.clear();
      drawColoredScreen(0x001F); // Blue
      health += 15;
      drawBottomText("You find a cave with shelter!\n(+15 health)");
    } else if (choice == Kywy::Events::KywyEvents::D_PAD_RIGHT_PRESSED) {
      // Mountain + Bridge = Dangerous crossing
      engine.display.clear();
      drawColoredScreen(0xF800); // Red
      health -= 20;
      score += 10;
      drawBottomText("The bridge is unstable!\n(+10 points, -20 health)");
    }
  }

  // Loop back to start
}

How It Works

Level 1 Choice: - Left: Takes you to the forest path (green screen) - Right: Takes you to the mountain path (dark screen)

Level 2 Choices: - Forest Path: Stream (treasure) or Hill (get lost) - Mountain Path: Cave (shelter) or Bridge (dangerous)

Each path has its own unique screen color and consequences!

Your Challenge

Add the nested structure to your existing game
Test both paths:
Forest → Stream: Should give +20 points
Forest → Hill: Should give -10 health
Mountain → Cave: Should give +15 health
Mountain → Bridge: Should give +10 points, -20 health

Questions to consider: - Which path gives the best results? - Which path gives the worst results? - How does the first choice affect your second choice options?

Why Use Nested Ifs?

Pros: - Different screens for different paths - More interesting story branches - Each choice feels more meaningful

Cons: - Code gets a bit more complex - Harder to see all possible paths

This is completely optional - your simple sequential choices work great too! In the next part, we'll learn how to add custom sprites to make your game look amazing. score += 40; health -= 30; drawBottomText("With sword and strength, you charge the dragon!\n(+40 points, -30 health)"); } else { // Wounded with sword - defensive drawColoredScreen(0xFFE0); // Yellow score += 25; health -= 10; drawBottomText("Your sword helps, but you're careful...\n(+25 points, -10 health)"); } } else { // No sword path with health check if (health > 40) { // Healthy without sword - risky drawColoredScreen(0xF800); // Red score += 15; health -= 25; drawBottomText("No weapon but you're strong! Barely survive...\n(+15 points, -25 health)"); } else { // Wounded without sword - desperate drawColoredScreen(0x2945); // Dark score += 5; health -= 15; drawBottomText("Unprepared and hurt... you struggle on.\n(+5 points, -15 health)"); } } } else if (choice == Kywy::Events::KywyEvents::D_PAD_RIGHT_PRESSED) { // Second right choice with nested logic engine.display.clear(); if (metWizard) { // Wizard path with score check if (score > 30) { // High score with wizard - magical drawColoredScreen(0x07FF); // Cyan health += 20; score += 20; drawBottomText("The wizard rewards your success!\n(+20 health, +20 points)"); } else { // Low score with wizard - helpful drawColoredScreen(0x001F); // Blue health += 15; score += 10; drawBottomText("The wizard aids your journey!\n(+15 health, +10 points)"); } } else { // No wizard path with health check if (health > 50) { // Healthy exploration drawColoredScreen(0x07E0); // Green score += 25; drawBottomText("You discover a hidden path!\n(+25 points)"); } else { // Wounded exploration - risky drawColoredScreen(0xF800); // Red score += 10; health -= 10; drawBottomText("The path is treacherous...\n(+10 points, -10 health)"); } } }

// THIRD CHOICE - Complex nested conditions choice = waitForInput();

if (choice == Kywy::Events::KywyEvents::D_PAD_LEFT_PRESSED) { // Third left choice - multiple nested conditions engine.display.clear(); if (hasSword && metWizard) { // Best case scenario if (health > 70 && score > 50) { drawColoredScreen(0x07E0); score += 50; drawBottomText("Perfect combination! Legendary victory!\n(+50 points) EPIC WIN!"); } else if (health > 40) { drawColoredScreen(0x07FF); score += 35; health += 10; drawBottomText("Sword and wizard magic prevail!\n(+35 points, +10 health)"); } else { drawColoredScreen(0xFFE0); score += 20; drawBottomText("Helpful allies, but you're wounded...\n(+20 points)"); } } else if (hasSword || metWizard) { // Partial advantages if (health > 60) { drawColoredScreen(0x07E0); score += 30; drawBottomText("One advantage helps you succeed!\n(+30 points)"); } else { drawColoredScreen(0xFFE0); score += 15; health -= 5; drawBottomText("Some help, but it's challenging...\n(+15 points, -5 health)"); } } else { // No advantages - tough path if (health > 30) { drawColoredScreen(0xF800); score += 10; health -= 20; drawBottomText("No help and it's dangerous...\n(+10 points, -20 health)"); } else { drawColoredScreen(0x2945); health -= 15; if (health <= 0) { drawBottomText("Completely unprepared... you fall.\nGAME OVER!"); } else { drawBottomText("Barely survive through determination!\n(-15 health)"); } } } } else if (choice == Kywy::Events::KywyEvents::D_PAD_RIGHT_PRESSED) { // Third right choice - alternative path engine.display.clear(); if (metWizard && score > 40) { // Wizard rewards high achievers drawColoredScreen(0x001F); health += 15; score += 25; drawBottomText("The wizard is impressed by your achievements!\n(+15 health, +25 points)"); } else if (hasSword && health > 50) { // Sword provides alternative victory drawColoredScreen(0x07E0); score += 30; drawBottomText("Your sword carves a path to victory!\n(+30 points)"); } else { // Default path drawColoredScreen(0x2945); score += 15; drawBottomText("You find an alternative route!\n(+15 points)"); } }

// FOURTH CHOICE - Show final results with nested win/lose choice = waitForInput();

engine.display.clear(); if (health <= 0) { // LOSE CONDITION drawColoredScreen(0xF800); // Red for defeat char loseText[64]; sprintf(loseText, "GAME OVER!\nFinal Score: %d\nHealth: %d", score, health); drawBottomText(loseText); } else { // WIN CONDITIONS - Nested based on score and health if (score >= 80 && health > 50) { drawColoredScreen(0x07E0); // Perfect victory char winText[64]; sprintf(winText, "LEGENDARY HERO!\nScore: %d Health: %d", score, health); drawBottomText(winText); } else if (score >= 60) { drawColoredScreen(0x07FF); // Good victory char winText[64]; sprintf(winText, "VICTORIOUS!\nScore: %d Health: %d", score, health); drawBottomText(winText); } else if (health > 30) { drawColoredScreen(0xFFE0); // Partial victory char winText[64]; sprintf(winText, "SURVIVED!\nScore: %d Health: %d", score, health); drawBottomText(winText); } else { drawColoredScreen(0xF800); // Pyrrhic victory char winText[64]; sprintf(winText, "VICTORY... at great cost.\nScore: %d Health: %d", score, health); drawBottomText(winText); } }

// Loop back to start for new adventure }

## Pros of Nested If Statements

### ✅ More Dynamic Gameplay
Choices change based on player state, creating replayability:
- Healthy players get aggressive options
- Wounded players get defensive options
- High-score players get riskier rewards

### ✅ Realistic Consequences
Decisions have lasting impact:
- Previous choices affect future options
- Health/score influence available paths
- Creates meaningful risk/reward systems

### ✅ Complex Storytelling
Enables sophisticated narratives:
- Character development through choices
- Branching storylines
- Multiple paths to the same ending

### ✅ Player Agency
Players feel their choices matter:
- Different playthroughs feel unique
- Strategic decision making
- Personal investment in outcomes

## Cons of Nested If Statements

### ❌ Code Complexity
Harder to read and maintain:
- Deep nesting creates "arrow code"
- Logic becomes harder to follow
- Debugging is more difficult

### ❌ Limited Scalability
Gets unwieldy with many conditions:
- Too many nested levels confuse logic
- Hard to add new features
- Code becomes brittle

### ❌ Testing Challenges
More combinations to test:
- Every health/score combination needs testing
- Edge cases multiply
- Regression testing becomes complex

## Best Practices for Nested Ifs

### 1. Limit Nesting Depth
Keep it to 2-3 levels maximum:
```cpp
// Good: Shallow nesting
if (mainCondition) {
  if (subCondition) {
    // Action
  }
}

// Bad: Deep nesting
if (condition1) {
  if (condition2) {
    if (condition3) {
      if (condition4) {
        // Too deep!
      }
    }
  }
}

2. Use Early Returns

Exit early to reduce nesting:

// Instead of deep nesting
if (health > 0) {
  if (score > 10) {
    if (hasSword) {
      // Deep nesting
    }
  }
}

// Use early returns
if (health <= 0) return; // Dead - exit early
if (score <= 10) return; // Not enough score - exit early
if (!hasSword) return;   // No sword - exit early
// Now we know player is alive, has score, and has sword
// Continue with main logic

3. Extract Complex Logic

Move nested logic to helper functions:

void handleHealthyPlayerChoices() {
  // All healthy player logic here
}

void handleWoundedPlayerChoices() {
  // All wounded player logic here
}

// Main loop becomes cleaner
if (health > 50) {
  handleHealthyPlayerChoices();
} else {
  handleWoundedPlayerChoices();
}

Your Challenge: Implement Nested Logic

Add health-based choice variations to your existing game
Create score-dependent rewards for risky choices
Implement different win conditions based on final health/score
Test different health levels to see how choices change

Questions to explore: - How does nested logic change player strategy? - When does nesting become too complex? - How can you balance dynamic choices with code maintainability?

In the next part, we'll learn how to add your own custom sprites using the online HPP generator tool!