# std::proj<div class="t-tr-text">(Std :: complexe)<div class="t-tr-dropdown"><div><div><div class="t-tr-dropdown-arrow-border"></div><div class="t-tr-dropdown-arrow"></div><div class="t-tr-dropdown-h">Original:</div><div class="t-tr-dropdown-orig">(std::complex)</div><div class="t-tr-dropdown-notes">The text has been machine-translated via [http://translate.google.com Google Translate].<br/> You can help to correct and verify the translation. Click [http://en.cppreference.com/w/Cppreference:MachineTranslations here] for instructions.</div></div></div></div></div>

< cpp‎ | numeric‎ | complex

Bibliothèque Numerics
Fonctions mathématiques courantes
Virgule flottante environnement
Nombres complexes
Tableaux numériques
La génération de nombres pseudo-aléatoires
Moment de la compilation arithmétique rationnelle (C++11)
Génériques des opérations numériques
Original:
Generic numeric operations
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 iota (C++11)
 accumulate
 inner_product
 partial_sum

Nombres complexes
Les fonctions membres
Original:
Member functions
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 complex::complex
 complex::operator=
 complex::real
 complex::imag
 complex::operator+=complex::operator-=complex::operator*=complex::operator/=
Tiers fonctions
Original:
Non-member functions
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 operator==operator!=
 operator<>
 real
 imag
 abs
 arg
 norm
 conj
 proj (C++11)
 polar
Les fonctions exponentielles
Original:
Exponential functions
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 exp
 log
 log10
Les fonctions de puissance
Original:
Power functions
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 pow
 sqrt
Les fonctions trigonométriques
Original:
Trigonometric functions
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 sin
 cos
 tan
 asin (C++11)
 acos (C++11)
 atan (C++11)
Fonctions hyperboliques
Original:
Hyperbolic functions
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 sinh
 cosh
 tanh
 asinh (C++11)
 acosh (C++11)
 atanh (C++11)

 Déclaré dans l'en-tête template< class T > complex proj( const complex& z ); (depuis C++11)
Renvoie la saillie du `z` nombre complexe sur la sphère de Riemann .
Original:
Returns the projection of the complex number `z` onto the Riemann sphere.
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Pour la plupart des `z`, std::proj(z)==z, mais tous les infinis complexes, même les numéros où un composant est infini et l'autre est NaN, deviennent positifs infini réel, (INFINITY, 0) ou (INFINITY, -0). Le signe de l'imaginaire (zéro) composant est le signe de std::imag(z) .
Original:
For most `z`, std::proj(z)==z, but all complex infinities, even the numbers where one component is infinite and the other is NaN, become positive real infinity, (INFINITY, 0) or (INFINITY, -0). The sign of the imaginary (zero) component is the sign of std::imag(z).
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## Sommaire

### [modifier]Paramètres

 z - valeur complexeOriginal: complex valueThe text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

### [modifier]Retourne la valeur

la projection de `z` sur la sphère de Riemann
Original:
the projection of `z` onto the Riemann sphere
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### [modifier]Exemple

```#include <iostream>
#include <complex>

int main()
{
std::complex<double> c1(1, 2);
std::cout << "proj" << c1 << " = " << std::proj(c1) << '\n';

std::complex<double> c2(INFINITY, -1);
std::cout << "proj" << c2 << " = " << std::proj(c2) << '\n';

std::complex<double> c3(0, -INFINITY);
std::cout << "proj" << c3 << " = " << std::proj(c3) << '\n';
}```

Résultat :

```proj(1,2) = (1,2)
proj(inf,-1) = (inf,-0)
proj(0,-inf) = (inf,-0)```

### [modifier]Voir aussi

 abs(std::complex) renvoie l'amplitude d'un nombre complexe Original: returns the magnitude of a complex number The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (fonction générique)  norm retourne la norme au carré Original: returns the squared magnitude The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (fonction générique)  polar construit un nombre complexe de magnitude et de l'angle de phase Original: constructs a complex number from magnitude and phase angle The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (fonction générique)