Квадратное уравнение

#include <stdio.h>
#include <iostream.h>
#include <math.h>
 
void main() {
    cout << "This is the program for solving quad equation\n";
    cout << "Your equation should have a view of Ax^2+Bx+C=0\n";
    cout << "Your A, B and C should be integer values aswell\n";
    cout << "Otherwise this program wont be able to solve your equation\n";
    int nABC[4];
    double nX[2];
    cout << "Now enter your A, B and C: ";
    cin >> nABC[0] >> nABC[1] >> nABC[2];
    cout << "\nSo your equation is: "<<nABC[0]<<"*x^2+"<<nABC[1]<<"*x+"<<nABC[2]<<"=0\n";
    cout << "First of all we should calculate D\n";
    nABC[3]=nABC[1]*nABC[1]-4*nABC[0]*nABC[2];
    cout << "Calculations are done and your D = " << nABC[3] << ", Be proud.\n";
    if (nABC[3]==0) {
        cout << "Your D=0 - this is awesome!\nNow we should calculate a solution\n";
        nX[0]= -nABC[1]/(2*nABC[0]);
        nX[1]=nX[0]; }
    if (nABC[3]>0) {
        cout << "Your D>0 - this is alright!\nNow we should calculate a solution\n";
        nX[0]=(-nABC[1]+sqrt(nABC[3]))/(2*nABC[0]);
        nX[1]=(-nABC[1]-sqrt(nABC[3]))/(2*nABC[0]); }
    if (nABC[3]<0) {
        cout << "OMG! Your D<0 - this is sad! This program isnt good enough to solve this case =(\n"; }
 
    if (nABC[3]>=0) {
        cout << "Calculations are done and your solution is: X(1)= "<< nX[0] << "  X(2)= "<<nX[1];}
        
    cout << "\nThere it is. Do you like it? [1/0]: ";       
    cin >> nABC[0]; 
    
return;
}