Step 3 / Select topic Go Easy

What this bank covers

• Unsigned integer wraparound in Go
• Integer vs floating-point division in Go
• Unsigned integer arithmetic wraps around in Go
• Untyped constant division in Go
• Integer division and remainder with negative operands in Go
• Signed integer overflow wraps in Go
• float64 is binary, not decimal
• fmt prints maps in sorted key order
• Ranging over an integer
• Interface equality compares the dynamic type too
• math.Sqrt and math.Pow
• Floating-point division by zero
• HasPrefix and HasSuffix test the ends of a string
• strings.Fields collapses runs of whitespace
• strings.TrimSpace strips leading and trailing whitespace
• In-order traversal of a binary search tree
• container/heap builds a min-heap from Less
• Multiple return values
• Functions as values
• select with a default case
• Atomic counter plus WaitGroup gives a deterministic total
• Go's &^ bit-clear operator
• rune is an alias for int32
• Operator precedence for * and +
• strings.Index and the missing-substring result
• strings.Split keeps empty fields
• strings.Replace with a count limit
• strings.Index returns a byte offset
• strings.Count and the empty substring
• strings.Repeat and strings.Join
• ranging over a map visits every key once
• range over a channel drains it until it is closed
• breaking out of a range-over-function iterator
• the range expression is evaluated once
• ranging over an array iterates a copy
• Range over a function iterator
• maps.Keys returns an iterator
• Slice capacity growth on append
• Missing map keys give the zero value
• Arrays are copied on assignment
• Traversing a singly linked list
• A slice used as a FIFO queue
• Comparable structs as map keys
• Sorting an int slice in place
• Block scope and shadowing
• Named results and deferred functions
• Package-level scope
• Arguments are passed by value
• recover stops a panic inside a deferred call
• Go switch cases do not fall through
• errors.Is unwraps %w chains
• break with a label exits the labeled loop
• defer runs on every return path
• Deferred calls can change a named result
• On error, Go functions return the zero value
• len and cap on a buffered channel
• Receiving from a closed channel
• sync.Once runs a function one time
• Mutex plus WaitGroup give a deterministic total
• select prefers a ready case over default
• context cancellation and ctx.Err
• sync.Once with concurrent goroutines
• Memoization returns the same value, faster
• Preallocating capacity avoids regrowth
• Binary search on a sorted slice
• Dynamic programming beats greedy for coin change
• Kadane's algorithm in one pass
• Sieve of Eratosthenes under 50
• 0/1 knapsack with a single DP row
• Exponentiation by squaring
• strings.Builder is an optimization, not a behaviour change
• Early exit does not change the first-match result
• string(rune(n)) versus strconv.Itoa(n)
• Struct copies: arrays by value, slices by reference
• Deferred arguments evaluate early, closures read late
• copy returns the number of elements copied
• strings.Count counts non-overlapping occurrences
• Collecting a range-over-func iterator
• time.Duration prints as formatted text
• Integer division and remainder with negative operands
• Unsigned integer overflow wraps around
• Sign of the % operator
• math.Round and halfway values
• Left shift as a power of two
• Floating-point equality
• math.Mod keeps the dividend's sign
• Square root then modulo in Go
• Ranging over a string
• Slice-backed stack pops in LIFO order
• Parameters are copies
• Closures capture variables, not copies
• recover with a named result
• fallthrough moves to exactly one more case
• Ranging over a closed channel
• Typed nil inside an interface
• Append writing into a shared backing array
• Rune count versus byte length