Defined in header <iomanip> | ||
---|---|---|
/*unspecified*/ setprecision( int n ); |
When used in an expression out << setprecision(n)
or in >> setprecision(n)
, sets the precision
parameter of the stream out
or in
to exactly n
.
n | - | new value for precision |
Returns an object of unspecified type such that if str
is the name of an output stream of type std::basic_ostream<CharT, Traits>
or an input stream of type std::basic_istream<CharT, Traits>
, then the expression str << setprecision(n)
or str >> setprecision(n)
behaves as if the following code was executed:
str.precision(n);
#include <iostream> #include <iomanip> #include <cmath> #include <limits> int main() { const long double pi = std::acos(-1.L); std::cout << "default precision (6): " << pi << '\n' << "std::setprecision(10): " << std::setprecision(10) << pi << '\n' << "max precision: " << std::setprecision(std::numeric_limits<long double>::digits10 + 1) << pi << '\n'; }
Output:
default precision (6): 3.14159 std::setprecision(10): 3.141592654 max precision: 3.141592653589793239
(C++11)(C++11) | changes formatting used for floating-point I/O (function) |
manages decimal precision of floating point operations (public member function of std::ios_base ) |
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