what does this line of code do? player = (player % 2) ? 1 : 2;

Question

I can`t understand this line why we use question mark "?" in it. there are 2 player 1 and 2 .

player = (player % 2) ? 1 : 2;

The line `(player % 2) ? 1 : 2` basically evaluates if `(player % 2)` is true. If it's true, the `1` is selected, otherwise, if it's false, the `2` is selected. The selected value is then assigned to `player`. — PerryC, Jan 13 '16 at 18:20

Violet Giraffe · Answer 1 · 2016-01-13T18:20:52.847

3

It's the ternary operator.

This line of code will set player to 1 if player originally was odd, and to 2 if it was even.

edited Jan 13 '16 at 18:20

answered Jan 13 '16 at 18:18

Violet Giraffe

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@juanchopanza: right. What I meant to say is it should be used for its return value, not for side effects. – Violet Giraffe Jan 13 '16 at 18:23

Danny_ds · Accepted Answer · 2016-01-13T22:04:52.370

3

This is a conditional if, and is the same as:

if(player % 2)
    player = 1; // Odd
else
    player = 2; // Even

Another way to do this without an if branch:

player = 2 - (player & 0x01);

The least significant bit is zero for even numbers.

edited Jan 13 '16 at 22:04

answered Jan 13 '16 at 18:19

Danny_ds

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score 0 · Answer 3 · answered Jan 13 '16 at 18:21

It's the ternary operator. It takes this form:

boolean expression ? a : b;

Which translates to:

If this expression is true, then a else b

It's often used as the right-hand expression in assignment operators. In your case player is being assigned 1 or 2 based on whether they are even or odd.

score 0 · Answer 4 · answered Jan 13 '16 at 18:22

0

It meaning that if the Condition is true so Player have the Value 1 else it have 2.

if(player % 2) {
    player = 1;
} else {
    player = 2;
}

answered Jan 13 '16 at 18:22

Andreas Schmidt

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what does this line of code do? player = (player % 2) ? 1 : 2;

4 Answers4