The long long data type stores extended size integer values. You can use a long long when your values are too large to fit into an int. A long long occupies 8 bytes of memory. This yields a range of approximately -9.2×10^18 to 9.2×10^18 (that’s 9.2 billion billion, or about 92 million times the number of stars in the Milky Way galaxy). The exact range of a long long on the Maple is from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807, or -2^63 to (2^63-1). A long long it is subject to the same overflow issues as any numeric data type.
A synonym for the long long type is int64.
Here’s an example of declaring a long long (see integer constants for an explanation of the “LL” at the end of the number):
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// Speed of light in nanometers per second (approximate).
long long c = 299792458000000000LL;
The general syntax for declaring an long long variable named var, then giving it value val, looks like:
long long var = val;
This is identical to the int syntax, with long long (or, at your option, int64) replacing int.
Note that long long values will still overflow, just like int values, but their much larger range makes this less likely to happen.
The downside to using a long long instead of an int (besides the extra storage) is that arithmetic operations on long longs will take slightly longer than on ints.
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Portions of this page were adapted from the Arduino Reference Documentation, which is released under a Creative Commons Attribution-ShareAlike 3.0 License.