/C++

# operator+,-,*,/ (std::complex)

 ```template< class T > complex operator+( const complex& lhs, const complex& rhs);``` (1) ```template< class T > complex operator+( const complex& lhs, const T& rhs);``` (2) ```template< class T > complex operator+( const T& lhs, const complex& rhs);``` (3) ```template< class T > complex operator-( const complex& lhs, const complex& rhs);``` (4) ```template< class T > complex operator-( const complex& lhs, const T& rhs);``` (5) ```template< class T > complex operator-( const T& lhs, const complex& rhs);``` (6) ```template< class T > complex operator*( const complex& lhs, const complex& rhs);``` (7) ```template< class T > complex operator*( const complex& lhs, const T& rhs);``` (8) ```template< class T > complex operator*( const T& lhs, const complex& rhs);``` (9) ```template< class T > complex operator/( const complex& lhs, const complex& rhs);``` (10) ```template< class T > complex operator/( const complex& lhs, const T& rhs);``` (11) ```template< class T > complex operator/( const T& lhs, const complex& rhs);``` (12)

Implements the binary operators for complex arithmetic and for mixed complex/scalar arithmetic. Scalar arguments are treated as complex numbers with the real part equal to the argument and the imaginary part set to zero.

1-3) Returns the sum of its arguments
4-6) Returns the result of subtracting `rhs` from `lhs`
7-9) Multiplies its arguments
10-12) Divides `lhs` by `rhs`

### Parameters

 lhs, rhs - the arguments: either both complex numbers or one complex and one scalar of matching type (`float`, `double`, `long double`)

### Return value

1-3) `complex<T>(lhs) += rhs`
4-6) `complex<T>(lhs) -= rhs`
7-9) `complex<T>(lhs) *= rhs`
10-12) `complex<T>(lhs) /= rhs`

Because template argument deduction does not consider implicit conversions, these operators cannot be used for mixed integer/complex arithmetic. In all cases, the scalar must have the same type as the underlying type of the complex number.

### Example

```#include <iostream>
#include <complex>
int main()
{
std::complex<double> c2(2, 0);
std::complex<double> ci(0, 1);

std::cout << ci << " + " << c2 << " = " << ci+c2 << '\n'
<< ci << " * " << ci << " = " << ci*ci << '\n'
<< ci << " + " << c2 << " / " << ci << " = " << ci+c2/ci << '\n'
<< 1  << " / " << ci << " = " << 1./ci << '\n';

//    std::cout << 1.f/ci; // compile error
//    std::cout << 1/ci; // compile error
}```

Output:

```(0,1) + (2,0) = (2,1)
(0,1) * (0,1) = (-1,0)
(0,1) + (2,0) / (0,1) = (0,-1)
1 / (0,1) = (0,-1)```