What happens if an integer is passed to a function that accepts an argument?.

The following steps will occur:

1. Memory will be allocated for the argument's value within the function's scope.
2. The value of the passed integer will be copied into this memory.
3. Inside the function, you can refer to this value by the parameter's name.
4. Changes to the parameter's value inside the function will not affect the original value passed during the call, since integer passing is by value (copy-by-value).

Example in Swift:

func processInteger(number: Int) {
    var mutableNumber = number // A copy of the value is created

    mutableNumber += 10 // Changes affect only the local copy
    print("Inside function: \(mutableNumber)")
}

var myInteger = 5
processInteger(number: myInteger)
print("Outside function: \(myInteger)") // Will print 5