Tracking Boolean State Changes
How do I handle situations where I need to track the history of boolean state changes?
When you need to remember previous boolean states, you can store the old value in a separate variable before updating the current state. This is especially useful for detecting changes or transitions in your program's state.
Basic State Tracking
Here's a simple example of tracking a state change:
#include <iostream>
using namespace std;
int main() {
bool wasAlive{true}; // Previous state
bool isAlive{true}; // Current state
int Health{100};
// Store the previous state before updating
wasAlive = isAlive;
// Update current state based on health
Health = Health - 150; // Take massive damage
isAlive = Health > 0;
// We can now check if the state just changed
bool justDied{wasAlive && !isAlive};
if (justDied) {
cout << "Game Over - you just died!\n";
} else if (!wasAlive && !isAlive) {
cout << "Still dead\n";
} else if (wasAlive && isAlive) {
cout << "Still alive\n";
}
}Game Over - you just died!Tracking Multiple State Changes
You can track multiple state changes by keeping multiple previous states:
#include <iostream>
using namespace std;
int main() {
// Track battle status
bool wasInCombat{false};
bool isInCombat{false};
bool hasWeapon{true};
// First update
wasInCombat = isInCombat;
isInCombat = true;
bool justEnteredCombat{
!wasInCombat && isInCombat};
if (justEnteredCombat) {
cout << "Combat started!\n";
if (!hasWeapon) {
cout << "Warning: Entered combat without "
"a weapon!\n";
}
}
// Second update
wasInCombat = isInCombat;
isInCombat = false;
bool justLeftCombat{
wasInCombat && !isInCombat};
if (justLeftCombat) {
cout << "Combat ended!";
}
}Combat started!
Combat ended!By storing the previous state, we can detect important transitions in our program, like when a player enters or leaves combat, when they gain or lose an ability, or when they cross important thresholds.
This is particularly useful in games and interactive applications where you need to trigger specific actions when states change.
Booleans - true and false values
An overview of the fundamental true or false data type, how we can create them, and how we can combine them.