Swift - Functions
How can you use nested functions to create a function that returns another function which adds a fixed number to its input?
Choose the correct Swift code.
How can you use nested functions to create a function that returns another function which adds a fixed number to its input? Choose the correct Swift code.
hard📝 Application Q15 of 15
Step-by-Step Solution
Solution:
Step 1: Understand the goal
We want a function that returns another function adding a fixed number 'x' to input 'y'.Step 2: Check each option's logic
func makeAdder(_ x: Int) -> (Int) -> Int { func adder(y: Int) -> Int { return x + y } return adder } defines nested 'adder' using 'x' and returns it correctly. func makeAdder(_ x: Int) -> Int { func adder(y: Int) -> Int { return x + y } return adder(5) } returns a value, not a function. func makeAdder(_ x: Int) -> (Int) -> Int { return func(y: Int) -> Int { x + y } } has invalid syntax. func makeAdder(_ x: Int) -> (Int) -> Int { func adder(y: Int) -> Int { return y } return adder } returns a function ignoring 'x'.Final Answer:
func makeAdder(_ x: Int) -> (Int) -> Int { func adder(y: Int) -> Int { return x + y } return adder } -> Option BQuick Check:
Nested function returns function adding x = func makeAdder(_ x: Int) -> (Int) -> Int { func adder(y: Int) -> Int { return x + y } return adder } [OK]
Quick Trick: Return nested function that uses outer parameter [OK]
Common Mistakes:
- Returning a value instead of a function
- Incorrect nested function syntax
- Ignoring outer function parameter inside nested function
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