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    std::setprecision

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    <tbody> </tbody>
    Déclaré dans l'en-tête <iomanip>
    /*unspecified*/ setprecision( int n );
    Lorsqu'il est utilisé dans une expression out << setprecision(n) ou in >> setprecision(n), définit le paramètre precision du flux out ou in exactement n .
    Original:
    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.
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    Paramètres

    n -
    nouvelle valeur pour la précision
    Original:
    new value for precision
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    Retourne la valeur

    Retourne un objet de type non précisé de sorte que si str est le nom d'un flux de sortie de std::basic_ostream<CharT, Traits> type ou un flux d'entrée de std::basic_istream<CharT, Traits> type, alors l'expression str << setprecision(n) ou str >> setprecision(n) se comporte comme si le code suivant est exécuté:
    Original:
    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:
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    str.precision(n);

    Exemple

    #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::precision(10):    " << std::setprecision(10) << pi << '\n'
              << "max precision:         "
              << std::setprecision(std::numeric_limits<long double>::digits10)
              << pi << '\n';
}

    Résultat : 

    default precision (6): 3.14159
std::precision(10):    3.141592654
max precision:         3.14159265358979324

    Voir aussi



    (C++11)
    (C++11)
    changements de formatage utilisés pour virgule flottante I / O
    Original:
    changes formatting used for floating-point I/O
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    (fonction) [edit]