Espaços nominais
Variantes
Acções

std::log

Da cppreference.com
< cpp‎ | numeric‎ | math

This page has been machine-translated from the English version of the wiki using Google Translate.

The translation may contain errors and awkward wording. Hover over text to see the original version. You can help to fix errors and improve the translation. For instructions click here.

Click here for the English version of this page

 
C++
 
Biblioteca numéricos
Funções matemáticas comuns
De ponto flutuante ambiente
Números complexos
Matrizes numéricas
Pseudo-aleatório de geração de números
Tempo de compilação aritmética racional (C++11)
Genéricos operações numéricas
Original:
Generic numeric operations
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
(C++11)
 
Funções matemáticas comuns
Funções
Original:
Functions
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
Operações básicas
Original:
Basic operations
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)(C++11)(C++11)
Funções exponenciais
Original:
Exponential functions
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
(C++11)
(C++11)
log
(C++11)
(C++11)
Funções de poder
Original:
Power functions
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
(C++11)
(C++11)
Funções trigonométricas e hiperbólicas
Original:
Trigonometric and hyperbolic functions
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
(C++11)
(C++11)
(C++11)
Erro e funções gamma
Original:
Error and gamma functions
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
(C++11)
(C++11)
(C++11)
(C++11)
Número inteiro mais próximo de operações de ponto flutuante
Original:
Nearest integer floating point operations
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
(C++11)(C++11)(C++11)
(C++11)
(C++11)
(C++11)(C++11)(C++11)
Flutuando funções de manipulação de pontos
Original:
Floating point manipulation functions
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
(C++11)(C++11)
(C++11)
(C++11)
(C++11)(C++11)
(C++11)
Classificação / Comparação
Original:
Classification/Comparison
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
Constantes de macros
Original:
Macro constants
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
(C++11)(C++11)(C++11)(C++11)(C++11)
 
Definido no cabeçalho <cmath>
float       log( float arg );
double      log( double arg );
long double log( long double arg );
double      log( Integral arg );
 (desde C++11)

Computes the natural (base e) logarithm of arg.

Índice

[editar] Parâmetros

arg -
flutuando valor de ponto
Original:
floating point value
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

[editar] Valor de retorno

natural logarithm of arg.

Erro de domínio ocorre se arg é negativo. NAN é devolvido em caso.
Original:
Domain error occurs if arg is negative. NAN is returned in that case.
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
Faixa de erro ocorre se arg é ​0​. -HUGE_VAL é devolvido em caso.
Original:
Range error occurs if arg is ​0​. -HUGE_VAL is returned in that case.
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

[editar] Exemplo

The following code computes the binary (base 2) logarithm with help of natural logarithm.

#include <cmath>
#include <iostream>
 
int main()
{
    double base = 2.0;
    double arg  = 256.0;
    double result = std::log(arg) / std::log(base);
 
    std::cout << result << '\n';
}

Saída: 

8

[editar] Veja também
retorna e elevado à potência dada (ex)
Original:
returns e raised to the given power (ex)
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

(função) [edit]
calcula comum (base 10) logaritmo (log10(x))
Original:
computes common (base 10) logarithm (log10(x))
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

(função) [edit]
levanta uma série para o poder dado (xy)
Original:
raises a number to the given power (xy)
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

(função) [edit]
logaritmo natural complexo com os cortes ao longo do ramo negativo do eixo real
Original:
complex natural logarithm with the branch cuts along the negative real axis
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

(modelo de função) [edit]
aplica-se a std::log função de cada elemento de valarray
Original:
applies the function std::log to each element of valarray
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

(modelo de função) [edit]
Obtida de "https://pt.cppreference.com/mwiki/index.php?title=cpp/numeric/math/log&oldid=21267"