Type Min Max -------------------------------- -------- ----------- signed n-bit int -2^(n-1) (2^(n-1))-1 unsigned n-bit int 0 (2^n)-1 IEEE float with n-bit mantissa -2^(n+1) 2^(n+1) #### Type Min Max -------------------------------- ----------------- ---------------- signed 32-bit integer -2147483648 2147483647 unsigned 32-bit integer 0 4294967295 IEEE float with 52-bit mantissa -9007199254740992 9007199254740992 #### $x = 2**(52+1); # For doubles, format "%.17e" will tell you if # the number is stored with no loss of precision # because log10(2**(n+1)) < 17. printf("%.17e\n\n", $x); $x -= 5; for (1..10) { printf("%f\n", $x); $x++; } #### 9.00719925474099200e+015 <-- That's exact. 9007199254740987.000000 9007199254740988.000000 9007199254740989.000000 9007199254740990.000000 9007199254740991.000000 9007199254740992.000000 9007199254740992.000000 <-- Least significant 9007199254740992.000000 bit dropped. 9007199254740992.000000 9007199254740992.000000