C :

#include<stdio.h>
int main()
{
   float a,b,c,x1,x2,delt;
   scanf("%f%f%f",&a,&b,&c);
   if(a==0)
   {
   	  if(b==0)
   	  {
   	  	 printf("No\n"); 
	  }
   	  else
   	  {
   	  	 x1=-c/b;
   	  	 printf("%f\n",x1);
	  }
   }
   else
   {
   	  delt=b*b-4*a*c;
   	  if(delt>0)
   	  {
   	  	 x1=(-b+sqrt(delt))/(2*a);
   	  	 x2=(-b-sqrt(delt))/(2*a);
   	  	 if(x1>x2)
   	  	 {
   	  	 	  printf("%f\n",x1);
   	  	 	  printf("%f\n",x2);
		 }
   	  	 else
   	  	 {
   	  	 	  printf("%f\n",x2);
   	  	 	  printf("%f\n",x1);
			  }
	  }
	  else if(delt==0)
	  {
	  	 x1=-b/(2*a);
	  	 printf("%f\n",x1);
	  }
	  else
	  {
	  	 printf("No\n");
	  }
   }
} 

C++ :

#include<stdio.h>
#include<iostream>
#include<math.h>
using namespace std;
int main()
{
	float a,b,c,delta;
	float x1,x2;
	cin>>a>>b>>c;
	delta= b*b-4*a*c;
	if(a==0 && b==0)
	{
		cout<<"No"<<endl;
	}
	else if(a==0 && b!=0)
	{
		printf("%.6f\n",-c*1.0/b);
	}
	else
	{
		if (delta>0)
		{
			x1 = (-b+sqrt(delta))/(2*a*1.0);
			x2 = (-b-sqrt(delta))/(2*a*1.0);
			if(x1>x2)
			{
				printf("%.6f\n%.6f\n",x1,x2);
			}
			else if(x2>x1)
			{
				printf("%.6f\n%.6f\n",x2,x1);
			}
			else
			{
				printf("%.6f\n",x1);
			}
		}
		else if ( delta == 0)
		{
			x1 =(-b)/(2*a*1.0);
			x2 = x1;
			printf("%.6f\n",x1);
		
		}
		else
		{
			cout<<"No"<<endl;
		}
	}
	return 0;

}

Java :

import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        double a = sc.nextDouble();
        double b = sc.nextDouble();
        double c = sc.nextDouble();
        if (a==0){
            if (b==0){
                System.out.println("No");
            }else{
                System.out.printf("%.6f\n",-c/b);
            }
        }else {
            double d = b*b-4*a*c;
            if (d<0){
                System.out.println("No");
            }else if (d==0){
                System.out.printf("%.6f\n",-b/(2*a));
            }else{
                double x1 = (-b+Math.sqrt(d))/(2*a);
                double x2 = (-b-Math.sqrt(d))/(2*a);
                x1 = (float)x1;
                x2 = (float)x2;
                if (x1>x2){
                    System.out.printf("%.6f\n",x1);
                    System.out.printf("%.6f",x2);
                }else{
                    System.out.printf("%.6f\n",x2);
                    System.out.printf("%.6f",x1);
                }
            }
        }
    }
}

Python :

# coding=utf-8
#python2
a,b,c = map(float,raw_input().split())
if a == 0 and b == 0:
    print("No")
if a == 0 and b != 0:
    x = -c/b
    print('%.6f'%x)
if a !=0:
    d = b*b-4*a*c
    if d < 0:
        print("No")
    if d == 0:
        x = -b/(2*a)
        print('%.6f' % x)
    if d > 0:
        x1 = (-b + d ** 0.5)/(2*a)
        x2 = (-b - d ** 0.5)/(2*a)
        print('%.6f'%x1)
        print('%.6f'%x2)