$ B = (0.1 + 0.7) * 10; echointval ($ B); why output 0.7?

{Code...} Why is 0.7 output? Not 0.8?

php




  $b=(0.1+0.7)*10;echo  intval($b);

Why is the output 0.7? Not 0.8?

Reply content:

php




  $b=(0.1+0.7)*10;echo  intval($b);

Why is the output 0.7? Not 0.8?

It is related to the nature of floating-point calculation. If you directly output $ B, you will find that the calculation result is 0.7999999, while intval is rounded down. You can use ceil instead.
See http://php.net/manual/en/language.types.integer.php#language.types.integer.casting

Let's take a look.$bBinary format:

Output:

ffffffffffff1f40

Becauselittle-endianIs actually0x401fffffffffffffAccordingIEEE754If the standard conversion is decimal

7.999999999999999

phpYou can useJavaTry the following code:

System.out.println(Double.longBitsToDouble(0x401fffffffffffffL));

The other content is clearly explained by the number of people upstairs ~

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