13.11 complex
| abs function template | Computes absolute value |
template<typename T> T abs (const complex<T>& z) |
The abs function returns the absolute value (or magnitude) of z .
See Also
polar function template, abs function in <cmath>
| arg function template | Computes argument (angle) |
template<typename T> T arg (const complex<T>& z) |
The arg function returns the argument (angle in polar coordinates) of z .
See Also
polar function template
| complex class template | Complex number template |
template<typename T> class complex { public: typedef T value_type ; complex (const T& re = T( ), const T& im = T( )); complex (const complex& z); template<typename X> complex (const complex<X>& z); T real ( ) const; T imag ( ) const; complex& operator= (const T& x); complex& operator+= (const T& x); complex& operator-= (const T& x); complex& operator*= (const T& x); complex& operator/= (const T& x); complex& operator= (const complex& z); template<typename X> complex& operator= (const complex<X>& z); template<typename X> complex& operator+= (const complex<X>& z); template<typename X> complex& operator-= (const complex<X>& z); template<typename X> complex& operator*= (const complex<X>& z); template<typename X> complex& operator/= (const complex<X>& z); }; |
The complex class template represents a complex number. The <complex> header specializes the template for the float , double , and long double types. You can instantiate complex<> for any type that behaves in the manner of the fundamental numeric types.
The type definition is a straightforward representation of a complex number. Basic assignment operators are defined as member functions, and arithmetic operators are defined as global functions.
- template<typename X> complex (const complex<X>& z)
-
Constructs a complex<T> object by copying the members from z . Effectively, this converts a complex object instantiated for one type to a complex object of another type.
- T real ( ) const
-
Returns the real part of *this .
- T imag ( ) const
-
Returns the imaginary part of *this .
- complex& operator= (const T& x)
-
Assigns x to the real part of *this and to the imaginary part. Returns *this .
- complex& operator+= (const T& x)
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Adds x to the real part of *this , leaving the imaginary part alone. Returns *this .
- complex& operator-= (const T& x)
-
Subtracts x from the real part of *this , leaving the imaginary part alone. Returns *this .
- complex& operator*= (const T& x)
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Multiplies the real and imaginary parts of *this by x . Returns *this .
- complex& operator/= (const T& x)
-
Divides the real and imaginary parts of *this by x . Returns *this .
- complex& operator= (const complex& z )
-
Assigns the real and imaginary parts of z to *this . Returns *this .
- template<typename X> complex& operator= (const complex<X>& z)
-
Assigns the real and imaginary parts of z to *this . Returns *this . Note that z and *this can have different template parameter types.
- template<typename X> complex& operator+= (const complex<X>& z)
-
Adds z to *this . Returns *this . Note that z and *this can have different template parameter types.
- template<typename X> complex& operator-= (const complex<X>& z )
-
Subtracts z from *this . Returns *this . Note that z and *this can have different template parameter types.
- template<typename X> complex& operator*=( const complex<X>& z)
-
Multiplies *this by z . Returns *this . Note that z and *this can have different template parameter types.
- template<typename X> complex& operator/= (const complex<X>& z)
-
Divides *this by z . Returns *this . Note that z and *this can have different template parameter types.
| complex<double> template specialization | Double-precision complex number |
template<> class complex<double> { public: typedef double value_type ; complex (double re = 0.0, double im = 0.0); complex (const complex<float>&); explicit complex (const complex<long double>&); double real ( ) const; double imag ( ) const; complex<double>& operator= (double); complex<double>& operator+= (double); complex<double>& operator-= (double); complex<double>& operator*= (double); complex<double>& operator/= (double); complex<double>& operator= (const complex<double>&); template<typename X> complex<double>& operator= (const complex<X>&); template<typename X> complex<double>& operator+= (const complex<X>&); template<typename X> complex<double>& operator-= (const complex<X>&); template<typename X> complex<double>& operator*= (const complex<X>&); template<typename X> complex<double>& operator/= (const complex<X>&); }; |
The complex<double> class is a straightforward specialization of the complex class template. It changes the operators to pass double parameters by value instead of by reference, and it adds a new constructor:
- explicit complex (const complex<long double>& z)
-
Constructs a complex number by copying from z . Note that you might lose precision or overflow, so the constructor is explicit .
| complex<float> template specialization | Single-precision complex number |
template<> class complex<float> { public: typedef float value_type ; complex (float re = 0.0f, float im = 0.0f); explicit complex (const complex<double>&); explicit complex (const complex<long double>&); float real ( ) const; float imag ( ) const; complex<float>& operator= (float); complex<float>& operator+= (float); complex<float>& operator-= (float); complex<float>& operator*= (float); complex<float>& operator/= (float); complex<float>& operator= (const complex<float>&); template<typename X> complex<float>& operator= (const complex<X>&); template<typename X> complex<float>& operator+= (const complex<X>&); template<typename X> complex<float>& operator-= (const complex<X>&); template<typename X> complex<float>& operator*= (const complex<X>&); template<typename X> complex<float>& operator/= (const complex<X>&); }; |
The complex<float> class is a straightforward specialization of the complex class template. It changes the operators to pass float parameters by value instead of by reference, and it adds two new constructors:
- explicit complex (const complex<double>& z)
- explicit complex (const complex<long double>& z)
-
Constructs a complex number by copying from z . Note that you might lose precision or overflow, so the constructors are explicit .
| complex<long double> template specialization | Extended-precision complex number |
template<> class complex<long double> { public: typedef long double value_type ; complex (long double re = 0.0L, long double im = 0.0L); complex (const complex<float>&); complex (const complex<double>&); long double real ( ) const; long double imag ( ) const; complex<long double>& operator= (const complex<long double>&); complex<long double>& operator= (long double); complex<long double>& operator+= (long double); complex<long double>& operator-= (long double); complex<long double>& operator*= (long double); complex<long double>& operator/= (long double); template<typename X> complex<long double>& operator= (const complex<X>&); template<typename X> complex<long double>& operator+= (const complex<X>&); template<typename X> complex<long double>& operator-= (const complex<X>&); template<typename X> complex<long double>& operator*= (const complex<X>&); template<typename X> complex<long double>& operator/= (const complex<X>&); }; |
The complex<long double> class is a straightforward specialization of the complex class template. It changes the operators to pass long double parameters by value instead of by reference.
| conj function template | Computes conjugate |
template<typename T> complex<T> conj (const complex<T>& z) |
The conj function returns the complex conjugate of z .
| cos function template | Computes cosine |
template<typename T> complex<T> cos (const complex<T>& z) |
The cos function returns the complex cosine of z .
See Also
cos function in <cmath>
| cosh function template | Computes hyperbolic cosine |
template<typename T> complex<T> cosh (const complex<T>& z) |
The cosh function returns the complex hyperbolic cosine of z .
See Also
cosh function in <cmath>
| exp function template | Computes exponential |
template<typename T> complex<T> exp (const complex<T>& z) |
The exp function returns the exponential of z , that is, e z .
See Also
exp function in <cmath>
| imag function template | Returns imaginary part |
template<typename T> T imag (const complex<T>& z) |
The imag function returns the imaginary part of z , that is, z.imag( ) .
See Also
abs function in <cmath>
| log function template | Computes natural logarithm |
template<typename T> complex<T> log (const complex<T>& z) |
The log function returns the complex natural (base e ) logarithm of z . The branch cuts are along the negative real axis, which means the imaginary part of the result is in the range [- 
i , i ].
See Also
log function in <cmath>
| log10 function template | Computes common logarithm |
template<typename T> complex<T> log10 (const complex<T>& z) |
The log10 function returns the complex common (base 10) logarithm of z . The branch cuts are along the negative real axis, which means the imaginary part of the result is in the range [- i , i ].
See Also
log10 function in <cmath>
| norm function template | Computes normalized value |
template<typename T> T norm (const complex<T>& z) |
The norm function returns the square of the absolute value of z .
See Also
abs function template
| operator+ function template | Persforms unary positive or addition |
template<typename T> complex<T> operator+ (const complex<T>& z); template<typename T> complex<T> operator+ (const complex<T>& x, const complex<T>& y); template<typename T> complex<T> operator+ (const complex<T>& x, const T& y); template<typename T> complex<T> operator+ (const T& x, const complex<T>& y); |
The unary positive operator returns z .
The binary addition operator returns the sum of its operands. If either operand is of type T , the argument is interpreted as the real part, with an imaginary part of T( ) or .
| operator- function template | Performs negation or subtraction |
template<typename T> complex<T> operator- (const complex<T>&); template<typename T> complex<T> operator- (const complex<T>&, const complex<T>&); template<typename T> complex<T> operator- (const complex<T>&, const T&); template<typename T> complex<T> operator- (const T&, const complex<T>&); |
The unary negation operator returns -z .
The binary subtraction operator returns the difference of its operands. If either operand is of type T , the argument is interpreted as the real part, with an imaginary part of T( ) or .
| operator* function template | Performs multiplication |
template<typename T> complex<T> operator* (const complex<T>&, const complex<T>&); template<typename T> complex<T> operator* (const complex<T>&, const T&); template<typename T> complex<T> operator* (const T&, const complex<T>&); |
The binary * operator performs complex multiplication. If either operand is of type T , the argument is interpreted as the real part, with an imaginary part of T( ) or .
| operator/ function template | Performs division |
template<typename T> complex<T> operator/ (const complex<T>&, const complex<T>&); template<typename T> complex<T> operator/ (const complex<T>&, const T&); template<typename T> complex<T> operator/ (const T&, const complex<T>&); |
The binary / operator performs complex division. If either operand is of type T , the argument is interpreted as the real part, with an imaginary part of T( ) or . Division by zero results in undefined behavior.
| operator== function template | Checks equality |
template<typename T> bool operator== (const complex<T>&, const complex<T>&); template<typename T> bool operator== (const complex<T>&, const T&); template<typename T> bool operator== (const T&, const complex<T>&); |
The == operator returns true if the real and imaginary parts of both values are equal. If either operand is of type T , the argument is interpreted as the real part, with an imaginary part of T( ) or .
| operator!= function template | Checks inequality |
template<typename T> bool operator!= (const complex<T>&, const complex<T>&); template<typename T> bool operator!= (const complex<T>&, const T&); template<typename T> bool operator!= (const T&, const complex<T>&); |
The != operator returns true if the real or imaginary parts are not equal. If either operand is of type T , the parameter is interpreted as the real part, with an imaginary part of T( ) or .
| operator<< function template | Writes a complex number |
template<typename T, typename charT, typename traits> basic_ostream<charT, traits>& operator<< (basic_ostream<charT, traits>&, const complex<T>& z); |
The << operator prints z to the output stream in the form (x, y) , in which x is the real part, and y is the imaginary part. Example 13-6 shows how z is formatted. If you want more control over the formatting, you must print the value yourself.
Example
Example 13-6. Formatting a complex number
template<class T, class charT, class traits> std::basic_ostream<charT, traits>& operator<<(std::basic_ostream<charT, traits>& o, const std::complex<T>& x) { std::basic_ostringstream<charT, traits> s; s.flags(o.flags( )); s.imbue(o.getloc( )); s.precision(o.precision( )); s << "(" << x.real( ) << "," << x.imag( ) << ")"; return o << s.str( ); } | operator>> function template | Reads a complex number |
template<typename T, typename charT, typename traits> basic_istream<charT, traits>& operator>> (basic_istream<charT, traits>&, complex<T>& z); |
The >> operator reads a complex number from an input stream into z . The input format can be any of the following:
- x
-
The value x is the real part, and T( ) or is the imaginary part.
- (x)
-
The value x is the real part, and T( ) or is the imaginary part.
- (x, y)
-
The value x is the real part, and y is the imaginary part.
| polar function template | Converts to polar coordinates |
template<typename T> complex<T> polar (const T& r, const T& theta) |
The polar function returns a complex object that represents the value given in polar coordinates, in which r is the magnitude and theta is the angle (in radians). The resulting value has the following real and imaginary parts:
real = r * cos(theta) imag = r * sin(theta)
See Also
abs function template, arg function template
| pow function template | Computes power |
template<class T> complex<T> pow (const complex<T>& x, int y); template<class T> complex<T> pow (const complex<T>& x, const T& y); template<class T> complex<T> pow (const complex<T>& x, const complex<T>& y); template<class T> complex<T> pow (const T& x, const complex<T>& y); |
The pow function returns the complex power xy . If x and y are both , the result is implementation-defined; otherwise , the result is exp(y * log(x)) . The branch cuts are along the negative real axis.
See Also
exp function template, log function template, pow function in <cmath>
| real function template | Returns real part |
template<typename T> T real (const complex<T>& z) |
The real function returns the real part of z , that is, z.real( ) .
| sin function template | Computes sine |
template<typename T> complex<T> sin (const complex<T>& z) |
The sin function returns the complex sine of z .
See Also
sin function in <cmath>
| sinh function template | Computes hyperbolic sine |
template<typename T> complex<T> sinh (const complex<T>& z) |
The sinh function returns the complex hyperbolic sine of z .
See Also
sinh function in <cmath>
| sqrt function template | Computes square root |
template<typename T> complex<T> sqrt (const complex<T>& z) |
The sqrt function returns the complex square root of z .The branch cuts are along the negative real axis. The result always has a nonnegative real part.
See Also
sqrt function in <cmath>
| tan function template | Computes tangent |
template<typename T> complex<T> tan (const complex<T>& z) |
The tan function returns the complex tangent of z .
See Also
tan function in <cmath>
| tanh function template | Computes hyperbolic tangent |
template<typename T> complex<T> tanh (const complex<T>& z) |
The tanh function returns the complex hyperbolic tangent of z .
See Also
tanh function in <cmath>
