Conditional operator

<h2 id="-and-">&& and ||</h2>
<p>In some programming languages, e.g. Java, the term <i>conditional operator</i> refers to <a href="/facts/Short-circuit_evaluation/GYhompFd">short circuit boolean operators</a>  && and ||. The second expression is evaluated only when the first expression is not sufficient to determine the value of the whole expression.<a class="footnote-ref" id="fnref:1" href="#fn:1"><sup>1</sup></a>
</p>
<h3>Difference from bitwise operator</h3>
<p>& and | are <a href="/facts/Bitwise_operation/0gkqnUda">bitwise operators</a> that occur in many programming languages. The major difference is that bitwise operations operate on the individual bits of a binary numeral, whereas conditional operators operate on logical operations. Additionally, expressions before and after a bitwise operator are always evaluated.
</p>
if (expression1 || expression2 || expression3)
<p>If expression 1 is true, expressions 2 and 3 are NOT checked.
</p>if (expression1 | expression2 | expression3)
<p>This checks expressions 2 and 3, even if expression 1 is true.
</p><p>Short circuit operators can reduce run times by avoiding unnecessary calculations. They can also avoid Null Exceptions when expression 1 checks whether an object is valid.
</p>
<h3>Usage in Java</h3>
class ConditionalDemo1 {

public static void main(String[] args) {
        int value1 = 1;
        int value2 = 2;
        if ((value1 == 1) && (value2 == 2))
            System.out.println("value1 is 1 AND value2 is 2");
        if ((value1 == 1) || (value2 == 1))
            System.out.println("value1 is 1 OR value2 is 1");
    }
}

<h2 id>"?:"</h2>
<p>In most programming languages, <a href="/facts/%253F%3a/3C8mgMD9">?:</a> is called the conditional operator. It is a type of <a href="/facts/Ternary_operator/u1byWRfT">ternary operator</a>. However, ternary operator in most situations refers specifically to <a href="/facts/%253F%3a/3C8mgMD9">?:</a>  because it is the only operator that takes three operands.<a class="footnote-ref" id="fnref:2" href="#fn:2"><sup>2</sup></a>
</p>
<h3>Regular usage of "?:"</h3>
<p>?: is used in conditional expressions. Programmers can rewrite an if-then-else expression in a more concise way by using the conditional operator.<a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a>
</p>
<h4>Syntax</h4>
condition ? expression 1 : expression 2
<p>condition: An expression which is evaluated as a <a href="/facts/Boolean_algebra/VkCToAmg">boolean</a> value.
</p><p>expression 1, expression 2: Expressions with values of any type.
</p><p>If the condition is evaluated to true, the expression 1 will be evaluated. If the condition is evaluated to false, the expression 2 will be evaluated.
</p><p>It should be read as: "If condition is true, assign the value of expression 1 to result. Otherwise, assign the value of expression 2 to result."
</p>
<h4>Association property</h4>
<p>The conditional operator is right-associative, meaning that operations are grouped from right to left. For example, an expression of the form a ? b : c ? d : e is evaluated as a ? b : (c ? d : e).<a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a>  The exception is <a href="/facts/PHP/02Lfe6RM">PHP</a>, in which it was left-associative prior to version 8, and is non-associative thereafter.<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a>
</p>
<h4>Examples by languages</h4>
<h5>Java</h5>
class ConditionalDemo2 {

public static void main(String[] args) {
        int value1 = 1;
        int value2 = 2;
        int result;
        boolean someCondition = true;
        result = someCondition ? value1 : value2;

System.out.println(result);
    }
}
<p>In this example, because <i>someCondition</i> is true, this program prints "1" to the screen. Use the ?: operator instead of an if-then-else statement if it makes your code more readable; for example, when the expressions are compact and without side-effects (such as assignments).
</p><h5>C++</h5>
#include <iostream>

int main() {
    int x = 1;
    int y = 2;
    std::cout << ( x > y ? x : y ) << " is the greater of the two." << std::endl;
}
<p>There are several rules that apply to the second and third operands in C++:
</p><ul><li>If both operands are of the same type, the result is of that type</li>
<li>If both operands are of arithmetic or enumeration types, the usual arithmetic conversions (covered in Standard Conversions) are performed to convert them to a common type</li>
<li>If both operands are of pointer types or if one is a pointer type and the other is a constant expression that evaluates to 0, pointer conversions are performed to convert them to a common type</li>
<li>If both operands are of reference types, reference conversions are performed to convert them to a common type</li>
<li>If both operands are of type void, the common type is type void</li>
<li>If both operands are of the same user-defined type, the common type is that type.<a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a></li></ul>
<h5>C#</h5>
// condition ? first_expression : second_expression;

static double sinc(double x) 
{
    return x != 0.0 ? Math.Sin(x) / x : 1.0;
}

<p>There are several rules that apply to the second and third operands <i>x</i> and <i>y</i> in C#:
</p>
<ul><li>If x has type X and y has type Y:</li>
<li>If an implicit conversion exists from X to Y but not from Y to X, Y is the type of the conditional expression.</li>
<li>If an implicit conversion exists from Y to X but not from X to Y, X is the type of the conditional expression.</li>
<li>Otherwise, no expression type can be determined, and a compile-time error occurs.</li>
<li>If only one of x and y has a type, and both x and y are implicitly convertible to that type, that type is the type of the conditional expression.</li>
<li>Otherwise, no expression type can be determined, and a compile-time error occurs.<a class="footnote-ref" id="fnref:7" href="#fn:7"><sup>7</sup></a></li></ul>
<h5>JavaScript</h5>
var age = 26;
var beverage = (age >= 21) ? "Beer" : "Juice";
console.log(beverage); // "Beer"

<p>The conditional operator of JavaScript is compatible with the following browsers:
</p><p><a href="/facts/Google_Chrome/4INfWq37">Chrome</a>, <a href="/facts/Microsoft_Edge/BGoJEFX9">Edge</a>, <a href="/facts/Firefox/xez2zv8H">Firefox</a> (1), <a href="/facts/Internet_Explorer/uL8a4Y5l">Internet Explorer</a>, <a href="/facts/Opera_(web_browser)/2NYCcTj1">Opera</a>, <a href="/facts/Safari_(web_browser)/9R8v7tNl">Safari</a>, Android webview, <a href="/facts/Google_Chrome_for_Android/4INfWq37">Chrome for Android</a>, <a href="/facts/Microsoft_Edge/BGoJEFX9">Edge Mobile</a>, <a href="/facts/Firefox_for_Android/6jBazUVR">Firefox for Android</a> (4), Opera for Android, Safari on IOS, <a href="/facts/Samsung_Internet/7hCehKlr">Samsung Internet</a>, <a href="/facts/Node.js/FKzhV4Qa">Node.js</a>.<a class="footnote-ref" id="fnref:8" href="#fn:8"><sup>8</sup></a>
</p>
<h3>Special usage in conditional chain</h3>
<p>The ternary operator is right-associative, which means it can be "chained" in the following way, similar to an if ... else if ... else if ... else chain.<a class="footnote-ref" id="fnref:9" href="#fn:9"><sup>9</sup></a>
</p>
<h4>Examples by languages</h4>
<h5>JavaScript</h5>
function example(…) {
    return condition1 ? value1
        : condition2 ? value2
        : condition3 ? value3
        : value4;
}

// Equivalent to:

function example(…) {
    if (condition1) { return value1; }
    else if (condition2) { return value2; }
    else if (condition3) { return value3; }
    else { return value4; }
}

<h5>C/C++</h5>
const double a =
	expression1	? a1
	: expression2	? a2
	: expression3	? a3
	: /*otherwise*/	a4;

// Equivalent to:

double a;
  if (expression1)
	a = a1;
  else if (expression2)
	a = a2;
  else if (expression3)
	a = a3;
  else /*otherwise*/
	a = a4;

<h3>Special usage in assignment expression</h3>
<p>the conditional operator can yield a <a href="/facts/Value_(computer_science)/QgQPbewf">L-value</a> in C/C++ which can be assigned another value, but the vast majority of programmers consider this extremely poor style, if only because of the technique's obscurity.<a class="footnote-ref" id="fnref:10" href="#fn:10"><sup>10</sup></a>
</p>
<h4>C/C++</h4>
((foo) ? bar : baz) = frink;

// equivalent to:
if (foo)
    bar = frink;
else
    baz = frink;

<h2 id="see-also">See also</h2>
<ul>
<li>Computer programming portal</li></ul>
<ul><li><a href="/facts/%253F%3a/3C8mgMD9">?:</a>, a conditional operator in computer programming</li>
<li><a href="/facts/Ternary_operation/u1byWRfT">Ternary operation</a></li>
<li><a href="/facts/Bitwise_operation/0gkqnUda">Bitwise operators</a></li>
<li><a href="/facts/Short-circuit_evaluation/GYhompFd">Short-circuit boolean operators</a></li>
<li><a href="/facts/Operator_(programming)/7TnU5LKu">Operator (programming)</a></li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>"Equality, Relational, and Conditional Operators (The Java™ Tutorials > Learning the Java Language > Language Basics)". docs.oracle.com. Retrieved 2019-04-29. <a href="https://docs.oracle.com/javase/tutorial/java/nutsandbolts/op2.html" target="_blank">https://docs.oracle.com/javase/tutorial/java/nutsandbolts/op2.html</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>BillWagner. "?: Operator - C# Reference". docs.microsoft.com. Retrieved 2019-04-29. <a href="https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/operators/conditional-operator" target="_blank">https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/operators/conditional-operator</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
<li id="fn:3"><p>"The ? : operator in Java". www.cafeaulait.org. Retrieved 2019-04-29. <a href="http://www.cafeaulait.org/course/week2/43.html" target="_blank">http://www.cafeaulait.org/course/week2/43.html</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li>
<li id="fn:4"><p>BillWagner. "?: Operator - C# Reference". docs.microsoft.com. Retrieved 2019-04-29. <a href="https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/operators/conditional-operator" target="_blank">https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/operators/conditional-operator</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li>
<li id="fn:5"><p>https://www.php.net/manual/en/language.operators.comparison.php#language.operators.comparison.ternary <a href="https://www.php.net/manual/en/language.operators.comparison.php#language.operators.comparison.ternary" target="_blank">https://www.php.net/manual/en/language.operators.comparison.php#language.operators.comparison.ternary</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li>
<li id="fn:6"><p>mikeblome. "Conditional Operator: ?". docs.microsoft.com. Retrieved 2019-04-29. <a href="https://docs.microsoft.com/en-us/cpp/cpp/conditional-operator-q" target="_blank">https://docs.microsoft.com/en-us/cpp/cpp/conditional-operator-q</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li>
<li id="fn:7"><p>BillWagner. "?: Operator - C# Reference". docs.microsoft.com. Retrieved 2019-04-29. <a href="https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/operators/conditional-operator" target="_blank">https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/operators/conditional-operator</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li>
<li id="fn:8"><p>"Conditional (ternary) operator - JavaScript". developer.mozilla.org. Retrieved 2019-04-29. <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Conditional_Operator" target="_blank">https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Conditional_Operator</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></p></li>
<li id="fn:9"><p>mikeblome. "Conditional Operator: ?". docs.microsoft.com. Retrieved 2019-04-29. <a href="https://docs.microsoft.com/en-us/cpp/cpp/conditional-operator-q" target="_blank">https://docs.microsoft.com/en-us/cpp/cpp/conditional-operator-q</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></p></li>
<li id="fn:10"><p>"Conditional Operator". wiki.c2.com. Retrieved 2019-04-29. <a href="http://wiki.c2.com/?ConditionalOperator" target="_blank">http://wiki.c2.com/?ConditionalOperator</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></p></li>
</ol>

Conditional operator open-in-new

Conditional operator