# Complex number: magnitude, squared magnitude and phase angle : complex number « Data Types « C++ Tutorial

```/* The following code example is taken from the book
* "The C++ Standard Library - A Tutorial and Reference"
* by Nicolai M. Josuttis, Addison-Wesley, 1999
*
* (C) Copyright Nicolai M. Josuttis 1999.
* Permission to copy, use, modify, sell and distribute this software
* is granted provided this copyright notice appears in all copies.
* This software is provided "as is" without express or implied
* warranty, and with no claim as to its suitability for any purpose.
*/
#include <iostream>
#include <complex>
using namespace std;

int main()
{
/* complex number with real and imaginary parts
* - real part: 4.0
* - imaginary part: 3.0
*/
complex<double> c1(4.0,3.0);

cout << "c1: " << c1 << endl;

/* create complex number from polar coordinates
* - magnitude: 5.0
* - phase angle: 0.75
*/
complex<float> c2(polar(5.0,0.75));

// print complex numbers as polar coordinates
cout << "c1: magnitude: " << abs(c1)
<< " (squared magnitude: " << norm(c1) << ") "
<<    " phase angle: " << arg(c1) << endl;
cout << "c2: magnitude: " << abs(c2)
<< " (squared magnitude: " << norm(c2) << ") "
<<    " phase angle: " << arg(c2) << endl;

}
```
```c1: (4,3)
c1: magnitude: 5 (squared magnitude: 25)  phase angle: 0.643501
c2: magnitude: 5 (squared magnitude: 25)  phase angle: 0.75```
 2.26.complex number 2.26.1. Create complex numbers based on double value 2.26.2. Plus two complex numbers together 2.26.3. Complex + integer 2.26.4. Use polar to create complex number 2.26.5. Complex number: magnitude, squared magnitude and phase angle 2.26.6. Complex conjugates 2.26.7. Complex number + float number 2.26.8. print sum of two complex numbers 2.26.9. Computing an Impedance with Complex Numbers 2.26.10. The << and >> operators are overloaded relative to complex numbers. 2.26.11. Add square root of two complex numbers and print the result