In this example, because someCondition 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).

The elseif statement, in the Ada language for example, is simply syntactic sugar for else followed by if. In Ada, the difference is that only one end if is needed, if one uses elseif instead of else followed by if .

An expression if a then b else c or a ? b : c evaluates to b if the value of a is true, and otherwise to c. One can read it aloud as "if a then b otherwise c".

Examples: {{#expr: ( {{{1}}} + {{{xshift}}} - 6 ) * 18.4 }} {{#expr: ln(7)^3 - abs(-0.344) + floor(5/3) round 3 }} {{#expr: {{{n}}} >0 and {{{n}}} <1.0 }} Note that these examples assume that all parameters referred to are defined and have numerical values. If this is not the case, errors will occur. See #iferror for one way to handle errors.

The dangling else is a problem in programming of parser generators in which an optional else clause in an if–then(–else) statement can make nested conditional statements ambiguous.

/expression/. test (string); // returns Boolean "string". search (/expression/); // returns position Number "string". replace (/expression/, replacement); // Here are some examples if (/Tom/. test ("My name is Tom")) console. log ("Hello Tom!"

While possibly confusing, this syntax is valid (X)HTML and is useful for conditional sections intended specifically for non-IE browsers; if the condition evaluates to true (for example, if targeting non-IE browsers and on some versions of IE), IE displays the - …

In any programming language that implements short-circuit evaluation, the expression x and y is equivalent to the conditional expression if x then y else x, and the expression x or y is equivalent to if x then x else y. In either case, x is only evaluated once.

If, for example, a variable should be changed to another value if its value evaluates to null, since C# 8.0 the ??= null coalescing assignment operator can be used:

A series of if-else conditionals that examine the target one value at a time. Fallthrough behavior can be achieved with a sequence of if conditionals each without the else clause. A lookup table, which contains, as keys, the case values and, as values, the part under the case statement.