norm

提取复数的准则。

template<class Type> 
   Type norm( 
      const complex<Type>& _ComplexNum 
   );

参数

• _ComplexNum
  将准则确定的复数。

返回值

复数的准则。

备注

复数的准则 a + bi 是 (a2 + b2*)。复数的准则是其模数正方形。 复数的模数是矢量长度的度量值且表示复数的。 复数的模数 a + bi 是 sqrt(a2 + b2),* written |a + bi|。

示例

// complex_norm.cpp
// compile with: /EHsc
#include <complex>
#include <iostream>

int main( )
{
   using namespace std;
   double pi = 3.14159265359;

   // Complex numbers can be entered in polar form with
   // modulus and argument parameter inputs but are
   // stored in Cartesian form as real & imag coordinates
   complex <double> c1 ( polar ( 5.0 ) );   // Default argument = 0
   complex <double> c2 ( polar ( 5.0 , pi / 6 ) );
   complex <double> c3 ( polar ( 5.0 , 13 * pi / 6 ) );
   cout << "c1 = polar ( 5.0 ) = " << c1 << endl;
   cout << "c2 = polar ( 5.0 , pi / 6 ) = " << c2 << endl;
   cout << "c3 = polar ( 5.0 , 13 * pi / 6 ) = " << c3 << endl;

   if ( (arg ( c2 ) <= ( arg ( c3 ) + .00000001) ) || 
        (arg ( c2 ) >= ( arg ( c3 ) - .00000001) ) )
      cout << "The complex numbers c2 & c3 have the "
           << "same principal arguments."<< endl;
   else
      cout << "The complex numbers c2 & c3 don't have the "
           << "same principal arguments." << endl;

   // The modulus and argument of a complex number can be recovered
   double absc2 = abs ( c2 );
   double argc2 = arg ( c2 );
   cout << "The modulus of c2 is recovered from c2 using: abs ( c2 ) = "
        << absc2 << endl;
   cout << "Argument of c2 is recovered from c2 using:\n arg ( c2 ) = "
        << argc2 << " radians, which is " << argc2 * 180 / pi
        << " degrees." << endl;
   
   // The norm of a complex number is the square of its modulus
   double normc2 = norm ( c2 );
   double sqrtnormc2 = sqrt ( normc2 );
   cout << "The norm of c2 given by: norm ( c2 ) = " << normc2 << endl;
   cout << "The modulus of c2 is the square root of the norm: "
        << "sqrt ( normc2 ) = " << sqrtnormc2 << "."; 
}

要求

复杂页眉： <>

命名空间: std