Quick Answer

Runtime crash from forced unwrapping of nil optionals

Understanding the Issue

This runtime error occurs when you force unwrap an optional (!) that contains nil. Always check for nil first or use safe unwrapping.

The Problem

This code demonstrates the issue:

Swift Error 
// Problem: Force unwrapping
var name: String? = nil
print(name!) // Crash

The Solution

Here's the corrected code:

Swift Fixed 
// Solution 1: Optional binding
if let name = name {
    print(name)
}

// Solution 2: Nil coalescing
print(name ?? "default")

// Solution 3: Guard statement
func process(name: String?) {
    guard let name = name else {
        print("No name provided")
        return
    }
    print(name)
}

Key Takeaways

Avoid force unwrapping - use safe optional handling techniques.