The size_t type is the unsigned integer type of the result of the sizeof operator. The underlying representation of variables Variables of type size_t are guaranteed to be of sufficient precision to represent the size of an object. The limit of size_t is specified by the SIZE_MAX macro.
Any variable that is used to represent the size of an object including, but not limited to, integer values used as sizes, indices, loop counters, and lengths should be declared as size_t.
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