[Solved] What is wrong with this Swift code?func doubleValue(_ num: inout Int) { num *= 2 } let fixedNum = 8 doubleValue(&fixedNum) | Swift

Swift - Functions

What is wrong with this Swift code?

func doubleValue(_ num: inout Int) {
    num *= 2
}

let fixedNum = 8
doubleValue(&fixedNum)

AInout parameters cannot be used with integers

BMissing & before fixedNum

CFunction should return a value instead

DCannot pass a constant as an inout parameter

Step-by-Step Solution

Solution:

Step 1: Identify the parameter type
The function expects an inout Int, meaning it will modify the passed variable.
Step 2: Check the argument passed
fixedNum is declared as a constant with let, so it cannot be modified.
Step 3: Understand Swift rules
Only variables declared with var can be passed as inout parameters.
Final Answer:
Cannot pass a constant as an inout parameter -> Option D
Quick Check:
Constants cannot be modified [OK]

Quick Trick: Only vars can be passed as inout [OK]

Common Mistakes:

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