Answer to Question #50430 in Visual Basic for Bob

Question

Why is the order of evaluation of arithmetic expressions important? Illustrate your answer with an example showing the effect parentheses can have on the way an expression is evaluated.

Answer 1

Answer:
Arithmetic operations in Visual Basic executes accordingto the common arithmetic rules:
1) Compiler evaluates expression fromleft to right
2) Multiplication and division havebigger priority then addition and substraction
3) Parentheses change evaluation order

Examples:
result =3 + 2 * 2 ' resultis 7
result =(3 + 2) * 2 ' resultis 10
result =3 + 2 * 4 / 2 ' resultis 7, first 2* 4, then 8 / 2, then 3 + 4
result =3 + 2 * 4 / 2 * 2 'result is 11, first -> 2* 4, then 8 / 2, then 4 * 2, then 3 + 8
result = 3 + 2 * 4 / (2 * 2) ' result is 5, first -> 2* 2, then 2 * 4, then 8 / 4, then 3+2

Dim a, b, c, d, e, f, g As Double
a = 8.0
b = 3.0
c = 4.0
d = 2.0
e = 1.0
f = (a - b) + ((c / d) * e) = (8 - 3) + ((4 / 2) * 1) = 7
Parentheses priority still from left to right andcannot be changed.