#515 – Binary Operators Are Left-Associative

When an expression contains more than one binary operators, where the operators are identical or have the same precedence, the operators are left-assocative.  This means that the expression is evaluated from left to right.

For example, the result of the expression shown below is 5, rather than 20.  80 is divided by 8 to get an intermediate result of 10.  10 is then divided by 2 to get a result of 5.

            double result = 80 / 8 / 2;

This means that the above expression is equivalent to:

            double result = (80 / 8) / 2;

If you want to force the division of the 2nd and 3rd operands to happen first, you could use parentheses around them:

            // result = 20
            double result = 80 / (8 / 2);

About Sean
Software developer in the Twin Cities area, passionate about software development and sailing.

3 Responses to #515 – Binary Operators Are Left-Associative

  1. Pingback: #1,074 – Use Parentheses in Expressions to Make Code More Readable | 2,000 Things You Should Know About C#

  2. Pingback: #1,075 – Operator Precedence Doesn’t Affect Operand Evaluation Order | 2,000 Things You Should Know About C#

  3. Mason says:

    This isn’t always true, especially not anymore.
    Exception when this post was written (which was indicated in the next post): assignment operators are right-associative, but they still qualify as binary operators.
    Exception that didn’t exist at the time: null-coalescing operators are also right-associative.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: