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C# C# Basics (Retired) Perfect Integers and Doubles

Posted by moonlightflower
moonlightflower
3,987 Points

C# Basics Integers and Doubles Quiz Q7

Hi, hoping someone can help me understand the maths in this question, I've tried several times and it just isn't clicking for me.

int a = 3;
int b = 2;
double c = 3.5;
double y = a / b * c;

y = ?

How I'm understanding it is:

First: b * c

2 * 3.5 = 7.0

Then: a / 7.0

3 / 7.0 = 0.4285714285714286

So: y = 0.4285714285714286

It's incorrect, so what am I doing wrong here..?

Fatemah Tavakoli
Fatemah Tavakoli
13,797 Points
Fatemah Tavakoli
Fatemah Tavakoli
13,797 Points

You have to consider the order of operations in math and also the type of variables (double and integer). Since we dont have parentheses and division and multiplication are in same order, we have to calculate them from left to right. First a\b = 3/2 = 1.5 but since a and b both of them are integer the result will be integer too => a/b = 1 And then 1 * 3.5 = 3.5.

Order of math operations: 1.Parentheses 2.Exponents 3.Multiplication and Division (from left to right) 4.Addition and Subtraction (from left to right)

moonlightflower
moonlightflower
3,987 Points

Thank you Fatima! Very clear and concise, I see what I did now.

Steven Parker
Steven Parker
229,644 Points
Steven Parker
Steven Parker
229,644 Points

fatima Tavakoli — You might consider posting your response as an answer instead of a comment. That would allow voting and give the original asker the option of selecting it as "best answer". If I were a mod, I'd promote it for you.

Fatemah Tavakoli
Fatemah Tavakoli
13,797 Points
Fatemah Tavakoli
Fatemah Tavakoli
13,797 Points

Steven Parker Thank you for pointing out :D I posted as an answer.

1 Answer

Fatemah Tavakoli
Fatemah Tavakoli
13,797 Points
Fatemah Tavakoli
Fatemah Tavakoli
13,797 Points

You have to consider the order of operations in math and also the type of variables (double and integer). Since we dont have parentheses and division and multiplication are in same order, we have to calculate them from left to right. First a\b = 3/2 = 1.5 but since a and b both of them are integer the result will be integer too => a/b = 1 And then 1 * 3.5 = 3.5.

Order of math operations:

  1. Parentheses.
  2. Exponents.
  3. Multiplication and Division (from left to right).
  4. Addition and Subtraction (from left to right).