Espaces de noms
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    floating point literal

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    Virgule flottante littéral définit une constante de compilation dont la valeur est indiquée dans le fichier source .
    Original:
    Floating point literal defines a compile-time constant whose value is specified in the source file.
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    Syntaxe

    A littéraux à virgule flottante ont deux syntaxes. La première est constituée des parties suivantes:
    Original:
    A floating-point literals have two syntaxes. The first one consists of the following parts:
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    • séquence non vide de chiffres décimaux contenant un point décimal (définit significatif)
      Original:
      nonempty sequence of decimal digits containing a decimal point character (defines significant)
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    • (en option) e ou E suivi avec moins optionnels ou signe plus et la séquence non vide de chiffres décimaux (définit exposant)
      Original:
      (en option) e or E followed with optional minus or plus sign and nonempty sequence of decimal digits (defines exponent)
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    • (en option) un spécificateur de type suffixe comme un l, f, L ou F
      Original:
      (en option) a suffix type specifier as a l, f, L or F
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    Le second est constitué des parties suivantes:
    Original:
    The second one consists of the following parts:
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    • séquence non vide de chiffres décimaux (définit significatif)
      Original:
      nonempty sequence of decimal digits (defines significant)
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    • e ou E suivi avec moins optionnels ou signe plus et la séquence non vide de chiffres décimaux (définit exposant)
      Original:
      e or E followed with optional minus or plus sign and nonempty sequence of decimal digits (defines exponent)
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    • (en option) un spécificateur de type suffixe comme un l, f, L ou F
      Original:
      (en option) a suffix type specifier as a l, f, L or F
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    Le type de suffixe spécificateur définit le type réel du littéral à virgule flottante:
    Original:
    The suffix type specifier defines the actual type of the floating-point literal:
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    • (Sans suffixe) définit double
      Original:
      (no suffix) defines double
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    • f F définit float
      Original:
      f F defines float
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    • l L définit long double
      Original:
      l L defines long double
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    Explication

    Une notation décimale scientifique est utilisée, ce qui signifie que l'exposant est la puissance de 10 par laquelle l'important est multiplied.
    Original:
    A decimal scientific notation is used, meaning that the exponent is the power of 10 by which the significant is multiplied.
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    Au sens mathématique du 123e4 est 123 × 10 4 </ sup>
    Original:
    The mathematical meaning of 123e4 is 123×104
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    Exemple

    std::cout << 123.456e-67 << '\n'
          << .1E4f       << '\n'
          << 58.         << '\n'
          << 4e2         << '\n';

    Résultat : 

    1.23456e-65
1000
58
400