在php [duplicate]中从float转换为Int

Question

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• explain php output 1 answer

I am trying to understand converting from a float to an int in PHP ,and came across the following code:

echo (int) ( (0.1+0.7) * 10 ); // echoes 7!

My question is why does it echo 7 instead of 8? What is the logic behind it?

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Answer 1

Because the actual value stored in memory is something like 7.999999999999999999999999 which is caused by rounding error.