echo (int) (100 * (7.77 - 7 )); Why 76 ?

[Gert Kok]

echo (100 * (7.77 - 7 )); --77
echo (int) (100 * (7.77 - 7 )); --76

Why the difference?

[PaulB]

Re: echo (int) (100 * (7.77 - 7 )); Why 76 ?

Gert Kok wrote:

echo (100 * (7.77 - 7 )); --77
echo (int) (100 * (7.77 - 7 )); --76
>
Why the difference?

http://uk3.php.net/manual/en/language.types.float.php

Read the warning.

Paul

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[C. (http://symcbean.blogspot.com/)]

Re: echo (int) (100 * (7.77 - 7 )); Why 76 ?

On 18 Mar, 19:30, "PaulB" <pb...@ntlworld .comwrote:

Gert Kok wrote:

echo (100 * (7.77 - 7 )); --77
echo (int) (100 * (7.77 - 7 )); --76

>

Why the difference?

>

http://uk3.php.net/manual/en/language.types.float.php

>
Read the warning.
>

This is not a PHP thing - most computer languages are like this except
for ones which deal with maths rather than arithmetic.

C.

[sheldonlg]

Re: echo (int) (100 * (7.77 - 7 )); Why 76 ?

Gert Kok wrote:

echo (100 * (7.77 - 7 )); --77
echo (int) (100 * (7.77 - 7 )); --76
>
Why the difference?

int(76.99999999 99999 ) ==76 (truncation)

while
76.999999999999 9 shown with no decimal places is rounded to 77

This is the same as in C, C++, Java, Fortran, Basic, etc. etc. etc.

Basically, there is no way to EXACTLY store a repeating decimal in 32
bits. Floating numbers (decimal points) are approximations. The casting
with (int) truncates this approximation.