I am dealing with a math example. I need to use 12 digit number for my code. So which datatype should i use, to use the number in my functions?
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If you have a 64-bit integer type, I'd go with that, since it gives you the (18 full digits) range:
−9,223,372,036,854,775,808 to
+9,223,372,036,854,775,807
For other tasks (even bigger integers or massive floating point values), I use GMP, the GNU multi-precision library. It's performance is impressive.
paxdiablo
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you can also use "unsigned long long" with format specifier "llu". It works fine for 12 digit number in C.
unsigned long long i=600851475143;
printf("%llu",i);
Prashant
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64-bit integers (long, int64_t, unsigned long, uint64_t) should do the trick, or if you need decimals, double or long double.
Delan Azabani
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3If you need decimals you're out of luck in pure C; `double` and `long double` are floating point types, not decimal ones. – Joey Aug 13 '10 at 11:33
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No. I *did* mention 64-bit integers too, which can hold well over 12 digits even when signed! – Delan Azabani Aug 13 '10 at 11:35
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what should i use for example while printing them? "%ld" was for long as far i remembered? – DesperateCoders Aug 13 '10 at 11:35
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Yes. `%ld` is the correct format specifier. Use `%lu` if it's an `unsigned long`, however. – Delan Azabani Aug 13 '10 at 11:35
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Check out `
`. It has printf() / scanf() format specifiers for the intX_t types (among others). – DevSolar Aug 13 '10 at 11:40 -
2You should not recommend `long` as a 64-bit type. It's 32-bit on most systems and the C standard only requires it to be at least 32-bit. – R.. GitHub STOP HELPING ICE Aug 13 '10 at 11:52
