Complex Numbers Problem

[xtlc]

I just googled myself for an hour and didn't find any usefull information, please help me out

I want to define 2 complex numbers and add them ... I found things like

complex<double>

complex<double>

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and stuff. But I dont get it to work correctly. I also tried including the <complex> library, but still no sucsess...

[anda_skoa]

Show your test program's code and the error you are getting.

No one here is a psychic.

Cheers,
_

[xtlc]

Oh I wasnt even that "far" but I will try:

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QPoint>
#include <QtCore>
#include <complex>
 
 
complex<double> a = -0.2i;
complex<double> b = 0.4i;
 
complex<double> c = a+b;
 
MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow) {
    ui->setupUi(this);
}
 
MainWindow::~MainWindow() {
    delete ui;
}

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QPoint>
#include <QtCore>
#include <complex>


complex<double> a = -0.2i;
complex<double> b = 0.4i;

complex<double> c = a+b;

MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow) {
    ui->setupUi(this);
}

MainWindow::~MainWindow() {
    delete ui;
}

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This already fails at "complex<double> a ..." with "complex does not name a type". I was not able to find a working example for just adding two complex numbers

[stampede]

complex is a part of std namespace

using namespace std;
 
// or
 
std::complex<double> i;

using namespace std;

// or

std::complex<double> i;

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[ChrisW67]

You will also need to construct the complex number objects correctly.

std::complex<double> a(0, -0.2);
std::complex<double> b(0,  0.4);
 
std::complex<double> result = a + b;

std::complex<double> a(0, -0.2);
std::complex<double> b(0,  0.4);

std::complex<double> result = a + b;

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[Radek]

complex<double> a = -0.2i;
complex<double> b = 0.4i;

complex<double> a = -0.2i;
complex<double> b = 0.4i;

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This isn't defined in C++. The compiler cannot compile "0.2i". As mentioned above, "i" is a predefined complex constant. Therefore:

complex<double> a = -0.2*i;
complex<double> b = 0.4*i;

complex<double> a = -0.2*i;
complex<double> b = 0.4*i;

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Naturally, you can use "i" in your computations, for example:

complex<double> c = i*(a + b) - 2*i;
complex<double> d = 5 + 6*i;

complex<double> c = i*(a + b) - 2*i;
complex<double> d = 5 + 6*i;

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The complex has a double() operator as well, you can:

complex<double> e = 6.6;

complex<double> e = 6.6;

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