Question

Given the following segment of code,

// postcondition:returns x + y public int add(int x, int y) {}
// postcondition:return x * y public int multiply(int x, int y) {}
which of the following corresponds to this expression?
multiply(add(multiply(a, b), add(multiply(a, c), multiply(b, c))), 2)
1.a * b + a * c + b * c * 2
2.a * b + a * c + b * c + 2
3.a * b + (a * c + b * c)
4.(a * b + a * c + b * c) * 2
5.2 * a * b + (a * c + b * c)

Answer 1

The whole line of code that performs an operation is this one:
multiply(add(multiply(a, b), add(multiply(a, c), multiply(b, c))), 2)

Let's do it step by step:
Step 1: Perform the inner group of parenthesis. Then expand going out, until you reach the bigger parenthesis.

Just bear in mind that multiply() = x * y
and add() = x + y


Last step: Get the final expression
( (a * b) + (a*c + b*c) )* 2