5月28日

编程题：36
import java.util.Scanner;

class Complex {
double real;
double imag;

public Complex(double real, double imag) {
    this.real = real;
    this.imag = imag;
}

public Complex add(Complex other) {
    return new Complex(real + other.real, imag + other.imag);
}

public Complex sub(Complex other) {
    return new Complex(real - other.real, imag - other.imag);
}

public Complex mul(Complex other) {
    double r = real * other.real - imag * other.imag;
    double i = real * other.imag + imag * other.real;
    return new Complex(r, i);
}

public Complex div(Complex other) {
    double denominator = other.real * other.real + other.imag * other.imag;
    double r = (real * other.real + imag * other.imag) / denominator;
    double i = (imag * other.real - real * other.imag) / denominator;
    return new Complex(r, i);
}

@Override
public String toString() {
    StringBuilder sb = new StringBuilder();
    if (Math.abs(real) < 1e-9 && Math.abs(imag) < 1e-9) {
        return "0.0";
    }
    if (Math.abs(real) >= 1e-9) {
        sb.append(String.format("%.1f", real));
    }
    if (imag > 1e-9) {
        sb.append("+").append(String.format("%.1f", imag)).append("i");
    } else if (imag < -1e-9) {
        sb.append(String.format("%.1f", imag)).append("i");
    }
    String res = sb.toString();
    if (res.endsWith(".0i")) {
        res = res.replace(".0i", "i");
    }
    if (res.startsWith("+")) {
        res = res.substring(1);
    }
    return res;
}

}

public class Main {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
double a1 = scanner.nextDouble();
double b1 = scanner.nextDouble();
double a2 = scanner.nextDouble();
double b2 = scanner.nextDouble();

    Complex c1 = new Complex(a1, b1);
    Complex c2 = new Complex(a2, b2);

    System.out.println("(" + formatComplex(c1) + ") + (" + formatComplex(c2) + ") = " + c1.add(c2));
    System.out.println("(" + formatComplex(c1) + ") - (" + formatComplex(c2) + ") = " + c1.sub(c2));
    System.out.println("(" + formatComplex(c1) + ") * (" + formatComplex(c2) + ") = " + c1.mul(c2));
    System.out.println("(" + formatComplex(c1) + ") / (" + formatComplex(c2) + ") = " + c1.div(c2));
}

public static String formatComplex(Complex c) {
    StringBuilder sb = new StringBuilder();
    sb.append(String.format("%.1f", c.real));
    if (c.imag >= 0) {
        sb.append("+");
    }
    sb.append(String.format("%.1f", c.imag)).append("i");
    String s = sb.toString();
    if (s.endsWith(".0i")) {
        s = s.replace(".0i", "i");
    }
    return s;
}

}