positive and negative infinity for integral types in c++ -


i reading positive , negative infinity in c++.

i read integral types dont have infinite value ie. std::numeric_limits<int>::infinity(); wont work, std::numeric_limits<int>::max(); work , represent maximum possible value can represented integral type.

so std::numeric_limits<int>::max(); of integral type taken positive infinite limit ?

or integral type has max value , infinity value not true ?

floating point numbers have special bit pattern indicate "the value infinity", used when result of operation defined infinite.

integer values have set number of bits, , bits used represent numeric value. there no "special bit pattern", it's whatever sum of bit positions mean.

edit: on page 315 of hardcopy of amd64 architecture programmer's manual, says

infinity. infinity positve or negative number +∞ , -∞, in integer bit 1, biased exponent maximum , fraction 0. infintes maximum numbers can represented in floating point format, negative infinity less finite number , positive infinity greater finite number (ie. affine sense).

and infinite result produce when non-zero, non-infinite number divided 0 or multiplied infinity, or when infinity added infinity or 0. arithmetic infinites exact. example, adding floating point number +∞ gives result of +∞ arithmetic comparisons work correctly on infinites. exceptions occur when use of infinity source operand constitutes invalid operation.

(any typing mistakes mine)


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