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A new operator was added to the C language in the last revision, one that I don’t cover in my books. (I’m not sure how that happened.) Anyway, it’s the Elvis operator. Unless you’re a fan of the ternary operator, you’ll probably never use it. And transform it into this goober:<\/p>\n In both code snippets, the greater of variables The ternary operator can’t replace all if-else<\/em> statements, but it works well in certain situations. In my code, I generally do the if-else<\/em> structure first and only later reduce it to the ternary operator — but only when such a simplifies the code. It’s rare that I first strive to use the ternary operator.<\/p>\n The ternary operator has its own reduction, known as the Elvis operator: Whereas the ternary operator represents this statement:<\/p>\n The Elvis operator works like this:<\/p>\n So the Elvis operator replaces the ternary operator only for specific conditions: When the first statement is true, that value is assigned. Otherwise the second value (or result) is assigned, whether that value is true or not.<\/p>\n Here’s a typical Elvis operator statement:<\/p>\n The value of variable In my code, I prefer to use the second set of statements because it’s readable. Still, the Elvis operator is available for those times you feel it’s necessary for obfuscation or it’s cool to use an operator named after a rock-and-roll legend.<\/p>\n Here’s sample code:<\/p>\n Sample run:<\/p>\n If you modify the voltage()<\/em> function to return the value zero, then the output becomes:<\/p>\n I’m unsure of the Elvis operator’s origins. In C, it’s implemented as the ternary operator, where the second part is missing. So, effectively:<\/p>\n is the same as<\/p>\n Some programming languages have strict syntax for the Elvis operator, with others using a different set of symbols or logical expressions instead.<\/p>\n","protected":false},"excerpt":{"rendered":" ?: Thank you. Thank you very much. Continue reading
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\nAs a review, the ternary operator is a delightfully cryptic way to represent a single if-else<\/em> choice. You can take code such as this:<\/p>\n\r\n if(a > b)\r\n c = a;\r\n else\r\n c = b;<\/pre>\n
\r\n c = a > b ? a : b;<\/pre>\n
a<\/code> or b<\/code> is assigned to variable c<\/code>.<\/p>\n?:<\/code> Apparently, enough people think of the ?:<\/code> characters as an Elvis Presley emoticon, so the operator is given his nickname.<\/p>\nresult<\/em> = comparison\/text<\/em> ? if_true<\/em> : if_false<\/em>;<\/code><\/p>\nresult<\/em> = if_true<\/em> ?: otherwise<\/em>;<\/code><\/p>\nr = voltage() ?: 120;<\/code><\/p>\nr<\/code> is set to the value returned by function voltage()<\/em>. If the value returned is zero (FALSE<\/code>), the value 120 is assigned instead. This statement is the equivalent of the following:<\/p>\n\r\n r = voltage();\r\n if( r == 0)\r\n r = 120;<\/pre>\n
\r\n#include <stdio.h>\r\n\r\nint voltage(void)\r\n{\r\n return(60);\r\n}\r\n\r\nint main()\r\n{\r\n int r;\r\n\r\n r = voltage() ?: 120;\r\n printf(\"Voltage is %d\\n\",r);\r\n\r\n return(0);\r\n}<\/pre>\nVoltage is 60<\/code><\/pre>\nVoltage is 120<\/code><\/pre>\nr = voltage() ?: 120;<\/code><\/p>\nr = voltage() ? voltage() : 120;<\/code><\/p>\n