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Decimal


echo 10; // Output 10
echo -1; // Output -1
echo 0; // Output 0
echo 1452; // Output 1452
(1/4)

Octal

This is Unix style access permision (identified by its leading zero)
          
echo 0100; // 64 = 1*8^2 + 0*8^1 + 0*8^0
(2/4)

Hexadecimal

Base 16 notation (identified by its leadgin 0x case-insensitive)

echo 0x111; // 1*16^2 + 1*16^1 + 1*16^0 = 256 + 16 + 1 = 273
echo 0x112; // 1*16^2 + 1*16^1 + 2*16^0 = 256 + 16 + 2 = 274
echo 0x121; // 1*16^2 + 2*16^1 + 1*16^0 = 256 + 32 + 1 = 289

echo 0xFFF; // 15*16^2 + 15*16^1 + 15*16^0 = 3840 + 240 + 15 = 4095
(3/4)

Float

Be aware that the float data type is not always capable of representing numbers in the way you expect it to.

echo ((0.1 + 0.7) * 10); // output 8
echo (int) ((0.1 + 0.7) * 10); // output 7
This happens because the result of this simple arithmetic expression is stored internally as 7.999999

Questions



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