Long integers not long enough

Ok, this is really basic, but I'm not sure why this doesn't work:

Code:

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long a = 1134903170;
long b = 1836311903;
printf("Stort tall: %li\n", a+b);

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And I'm not sure if the problem is with the %li in the printf or with the resulting long getting too big for the long type?

1134903170 + 1836311903 = 2971215073. Assuming you're on a typical 32-bit system, LONG_MAX will likely be 2147483647, which means you're overflowing the data type.

Hm. Yes, since Mint/Ubuntu 64-bit isn't very stable, I'm running a 32-bit system. How to get around this? Use hex? :-)

Quote:

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Originally Posted by cnewbie1

Hm. Yes, since Mint/Ubuntu 64-bit isn't very stable, I'm running a 32-bit system. How to get around this? Use hex? :-)

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If you need integers to be a specific width, don't use the standard types. Instead, #include <stdint.h> and use (in your case) int64_t or uint64_t.

>How to get around this? Use hex? :-)
Using hexadecimal doesn't change the length of your data type. If you're using a compiler that supports some form of the long long type, that would be your best bet. Otherwise, consider an arbitrary length math library like GMP.

>Instead, #include <stdint.h> and use (in your case) int64_t or uint64_t.
This assumes C99, which still isn't widely adopted enough to justify the assumption.

Ah, I've learned something today too :-) (int64_t is a template, isn't it?)

However, how do I specify an int64_t integer in printf?

EDIT: Nevermind. I found it out: printf("%lli...

You can try

Code:

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long long a = 1134903170;
unsigned long long b = 1836311903;

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These types comes with C99, but newer MSVC compilers (not C99) know also know these types.

I need to ask this question again:

I'm trying to assign the value 600851475143 to a variable, but even the int64_t cannot handle that. What do I use here?

Use a double and accept some loss of precision, or use a bignum library like GMP: The GNU MP Bignum Library

Quote:

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Originally Posted by cnewbie1

I need to ask this question again:

I'm trying to assign the value 600851475143 to a variable, but even the int64_t cannot handle that. What do I use here?

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An 64bit integer can surely handle that value! Are you sure you arenot doing something wrong? ( Unless your compiler doesnot support 64bit )

Quote:

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Originally Posted by cnewbie1

I'm trying to assign the value 600851475143 to a variable, but even the int64_t cannot handle that. What do I use here?

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You could try 600851475143L or 600851475143UL to see if it makes any difference.

The highest number for a signed 64bit intiger is 9223372036854775807
Your value is 600851475143, it should fit.

I'm wondering how you're assigning it...

Quote:

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Originally Posted by laserlight

You could try 600851475143L or 600851475143UL to see if it makes any difference.

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Don't you mean 600851475143LL or 600851475143ULL?

Oh yes, I do. The LL in my own username betrayed me.

I'm using gcc on a Linux 32-bit system (32-bit because 64-bit simply isn'g stable enough, unfortunately).

When I use this line:

Code:

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int64_t longnumer = 600851475143;

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gcc gives this warning:

Code:

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warning: integer constant is too large for ‘long’ type

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Adding LL seems to work, though.