Quick Answer
Attempting to change a let-declared constant
Understanding the Issue
Swift constants declared with let are immutable. This error occurs when trying to modify them after initialization.
The Problem
This code demonstrates the issue:
Swift
Error
// Problem: Modifying constant
let count = 5
count += 1 // ErrorThe Solution
Here's the corrected code:
Swift
Fixed
// Solution 1: Use var if mutable
var count = 5
count += 1
// Solution 2: Create new value
let count = 5
let newCount = count + 1Key Takeaways
Use let for constants and var for variables that need to change.