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std::abs(float), std::fabs

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Common mathematical functions
Functions
Basic operations
abs(float)fabs
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
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(C++11)(C++11)(C++11)
Exponential functions
(C++11)
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Power functions
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Trigonometric and hyperbolic functions
(C++11)
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Error and gamma functions
(C++11)
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Nearest integer floating point operations
(C++11)(C++11)(C++11)
(C++11)
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(C++11)(C++11)(C++11)
Floating point manipulation functions
(C++11)(C++11)
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(C++11)(C++11)
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Classification/Comparison
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Macro constants
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Defined in header <cmath>
float       abs( float arg );
(1)
double      abs( double arg );
(2)
long double abs( long double arg );
(3)
float       fabs( float arg );
(4)
double      fabs( double arg );
(5)
long double fabs( long double arg );
(6)
double      fabs( Integral arg );
(7) (since C++11)
1-6) Computes the absolute value of a floating point value arg.
7) A set of overloads or a function template for all combinations of arguments of arithmetic type not covered by 4-6). If any argument has integral type, it is cast to double. If any other argument is long double, then the return type is long double, otherwise it is double.

Contents

[edit] Parameters

arg - Value of a floating-point or Integral type

[edit] Return value

If successful, returns the absolute value of arg (|arg|). The value returned is exact and does not depend on any rounding modes.

[edit] Error handling

This function is not subject to any of the error conditions specified in math_errhandling

If the implementation supports IEEE floating-point arithmetic (IEC 60559),

  • If the argument is ±0, +0 is returned
  • If the argument is ±∞, +∞ is returned
  • If the argument is NaN, NaN is returned

[edit] Example

#include <iostream>
#include <cmath>
 
int main()
{
    std::cout << "abs(+3.0) = " << std::abs(+3.0) << '\n'
              << "abs(-3.0) = " << std::abs(-3.0) << '\n';
    // special values
    std::cout << "abs(-0.0) = " << std::abs(-0.0) << '\n'
              << "abs(-Inf) = " << std::abs(-INFINITY) << '\n';
}

Possible output:

abs(+3.0) = 3
abs(-3.0) = 3
abs(-0.0) = 0
abs(-Inf) = inf

[edit] See also

computes absolute value of an integral value (|x|)
(function) [edit]
(C++11)
copies the sign of a floating point value
(function) [edit]
(C++11)
checks if the given number is negative
(function) [edit]
returns the magnitude of a complex number
(function template) [edit]
applies the function std::abs to each element of valarray
(function template) [edit]