[c] How do I get DOUBLE_MAX?

AFAIK, C supports just a few data types:

int, float, double, char, void enum.

I need to store a number that could reach into the high 10 digits. Since I'm getting a low 10 digit # from

INT_MAX

, I suppose I need a double.

<limits.h> doesn't have a DOUBLE_MAX. I found a DBL_MAX on the internet that said this is LEGACY and also appears to be C++. Is double what I need? Why is there no DOUBLE_MAX?

Using double to store large integers is dubious; the largest integer that can be stored reliably in double is much smaller than DBL_MAX. You should use long long, and if that's not enough, you need your own arbitrary-precision code or an existing library.

INT_MAX is just a definition in limits.h. You don't make it clear whether you need to store an integer or floating point value. If integer, and using a 64-bit compiler, use a LONG (LLONG for 32-bit).

Its in the standard float.h include file. You want DBL_MAX

You are looking for the float.h header.

You get the integer limits in <limits.h> or <climits>. Floating point characteristics are defined in <float.h> for C. In C++, the preferred version is usually std::numeric_limits<double>::max() (for which you #include <limits>).

As to your original question, if you want a larger integer type than long, you should probably consider long long. This isn't officially included in C++98 or C++03, but is part of C99 and C++11, so all reasonably current compilers support it.