10-26 Exercise 3: Find roots of a quadratic equation

Question

Write a program to find roots of a quadratic equation

A quadratic equation is a second order equation having a single variable. Any quadratic equation can be represented as where a, b and c are constants ( a can't be 0) and x is unknown variable. 

寫一個找二次方程的求根程式

For Example

 is a quadratic equation where a, b and c are 2, 5 and 3 respectively.

To calculate the roots of quadratic equation we can use below formula. There are two solutions of a quadratic equation.

使用下列公式:

x = (-b + sqrt(D))/(2*a)
x = (-b - sqrt(D))/(2*a)

where, D = (b*b-4*a*c) is Discriminant (判別式), which differentiate the nature of the roots of quadratic equation.

For the complex result (複數根):

realPart = -b/(2*a);
imaginaryPart =sqrt(-D)/(2*a);

Note: We have used sqrt() function to find square root which is in math.h library.

 

Example input 1:

1 2 1

Example output 1:

Roots of 1.00x^2 + 2.00x + 1.00 = 0 are real and same
x1 = x2 = -1.00

 

Example input 2:

1 -3 2

Example output 2:

Roots of 1.00x^2 + -3.00x + 2.00 = 0 are real and different
x1 = 2.00
x2 = 1.00

 

Example input 3:

1 2 2

Example output 3:

Roots of 1.00x^2 + 2.00x + 2.00 = 0 are complex and different
x1 = -1.00+1.00i
x2 = -1.00-1.00i

Comments

We will continue this question in few days

---

Everything is fixed. Enjoy your time with The Judge :)

---

ANNNNNNNNNNNNNNNNNNNNNNNNNNGRYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY

---

Your code has newline at the end sometime. You learned this lesson many times!

---

After i correct the newline in my code,there is still wrong output.However,I had run the program in Codeblocks.The output is still as well as the result. Seeking for help.

---

your output lack of 1 space at line 8 when print out "Roots of ...". Please be careful with all small details when working with online judge

Answer 1

Hidden content!
#include <stdio.h>
  ** * *     *  * * **
int main()
{
****  * *      ** **  **     *  **** *** * * ** ****
  *  ** *  *    ** *****  **   ** * * *  * %f *  ** * ***   ** ** ***   * ** 
*  *   *  *   ***  **    * = (b*b-4*a*c);
* *  ****  *     *  *** ***   = (-b + sqrt(D))/(2*a);
  *         ** *  *      ** = (-b - sqrt(D))/(2*a);
** **  ****  ** **  **   *  **  = -b/(2*a);
* *     * *  ***   * * *   *   * ****   =sqrt(-D)/(2*a);
 ****  *******   ** *    *****
  ****   * *      * ****    *
**   *  * * *  * *  *  *** ** *** * ** * *** * ***   * *    * **  of %.2fx^2 + %.2fx + %.2f = 0 are real and  *   *** **  *** *  * * 
**** **** **   ******    ** *  **   ** *** * * * * ** *******   ** = %.2f\nx2 = %.2f",x1,x2);
   *** *** *   ***     *** ***

* ** **  **    ******  ** ** *   if(D==0)
*** *   *    ** *  * *** *
   *  *  *  *  *  * *   * *    ********  *****    *     **  ** *  *    **    of %.2fx^2 + %.2fx + %.2f = 0 are real and same\n",a,b,c);
*   * *  *  * * * ****** *   ** *   *****   * * ***     *    *** *  = x2 = %.2f",x1);
*  * * * * * ****  *    
** * ** **    **  * *
* ** * ** * **** *
* * *    ****  *   *  *  ***  *** ** *   *** *             ********** of %.2fx^2 + %.2fx + %.2f = 0 are complex and  **  **   *  *  * 
**   *   *   **   ********  ***  **  ***  *** * *** *  * *****  *    *   =  ****  * *** **   * *  *   ****
* ***** ***  ** *  ****  *** ** * * *   * ** *** **  * * *     * = * * *     **** **** * * ** ** *****
  *  ** ** ******  *  * *   
 ** * *     * * ** *   ***** ** * 0;
}

Comments

Case 0: Correct output
Case 1: Correct output
Case 2: Correct output
Case 3: Correct output

Answer 2

Hidden content!
#include <stdio.h>
 ** *  **  ***  ** **** *
int main()
{
*** *  * **   *** *  *    *  **     * *****  *
*  **    *       * *    * *  * ******  %f **  * *   *    **  * *** *  ** **
 *  * **      * * ** ***  = (b*b-4*a*c);
   * **     * * *  *  *       = (-b + sqrt(D))/(2*a);
** *  * * *  ******* *  **   = (-b - sqrt(D))/(2*a);
*****   **    **   *   *    *   = -b/(2*a);
 * ****  *  *  * ** * **  ***   *** * *  =sqrt(-D)/(2*a);
*** *** *  *     *  * *****  *****    *   *
** *     *   *  *  *      * *   **
*** **  ** **      ** *  *   ****** **  **  *  *   *** * * * ****  **  of %.2f x^2 + %.2f x + %.2f = 0 are real and * ****** *  *** *
**  * ** ******   **  *  * **** *   *  *   * **  *   **  *   *  = %.2f\nx2 = %.2f",x1,x2);
*** ****    *  * **     ***

        *    **   *   *  ** if(D==0)
**  **    ** * ****  ***  * ****
** **     ***** *    ***  **  *** * **   * **   * ** ** *  ***  of %.2fx^2 + %.2fx + %.2f = 0 are real and same\n",a,b,c);
****    * *    *  **  *  **    *  *  *  *  * *   *** * * ** *  = x2 = %.2f",x1);
** **  * ** **    *    * ** 
* * *   *  *  * *********  **   
** *  ***  ***    ** ** **
* *  **   *  *  *  **** *****  * *** *  * * ** *  *   ** **    **** of %.2fx^2 + %.2fx + %.2f = 0 are complex and  *** * * *  *  
 **  ****  **  * ** ** *** *   **   *  ***  *****   *****     *** *  =  **  * * **** *  *   * ***    *
  *  **   *  ** **  **  * **   * ** * ** * **   * *  *****  *  *  * **   = **** * ** ** * * ********
  * **  ******* * *  * *  ***
 * *****  ***     * * * ******** * 0;
}

Comments

Case 0: Correct output
Case 1: Wrong output
Case 2: Correct output
Case 3: Wrong output

Answer 3

Hidden content!
#include <stdio.h>
#include <stdlib.h>

int main()

{
* *** *  * ** * *  * * *** * * a,b,c,x1,x2,D=0;
   ** **   **   **** ****    * ** 
**** * *  * *** **  ** * * *      * **** * %f   * **  * ** ****** * * * *  ****  
 * *** **  **   **  **  * ***
 * ** * * * **     *** **  *  ** 
 *    ***  *******  *        + sqrt(D))/(2*a);
   ** ** *** ***** **** ** ****   - sqrt(D))/(2*a);
**      *   *  * * *    ***
   ** * *  *   * * * ** *   ***  *****
**    *  *  *   **   *** 
** ** *     *    * * *  ****   *****    *  **   ***  ***    **** of %.2fx^2+%.2fx+%.2f=0 are complex and  ** *   * **    *  ** ********
  *     ***     ****** *  * **  
  **   *    **  **  
*** **  * **** *  * ** *  if(D==0)
**  * ***  *  **** ** ***  *** 
     * *   * *** * *****  *  *  **** ** *      * * ****   ***  of %.2fx^2+%.2fx+%.2f=0 are real and same\nx1=x2=%.2f",a,b,c,x1);
 *    * ******* ** *  **
   ********* *** ***** 
*  ***** *    **   ***  *****
* ** * *  ** *  * ***  **  * *
***** *  ******* ** **  ** ****   **    **   *      ** **** * *  of %.2fx^2+%.2fx+%.2f=0 are real and **  *   *  **** **  **   * ** ****** 
 * *  *   * **  ***   ***** 
*******   *  ** *  * *** * ** 
*** *****  ** *  ***     
  *** * ** * ** ***     ** **  *** 0;
}

Comments

prog.c: In function 'main':
prog.c:12:14: warning: implicit declaration of function 'sqrt' [-Wimplicit-function-declaration]
     x1=(-b + sqrt(D))/(2*a);
              ^~~~
prog.c:12:14: warning: incompatible implicit declaration of built-in function 'sqrt'
prog.c:12:14: note: include '<math.h>' or provide a declaration of 'sqrt'

Answer 4

Hidden content!
***  **  * **  * 
int main()
{
 *** ***     **   ***  *   **  a,b,c,D;
* *     **   ** **  *   * * * ** x1,x2,r,i;
* *   ** * ** * ** ****   *   * *   * ** ** **  ******  ** **** * *  * *  
**  *   *   *  **   *   **   *   *  ** ***
  ** * *  *** *     * ***  *  * **** * **
 ** **     **  ***  *  ** **   ** **     **    **
* ***  * ** * **   *  * *** *    
    * *    **  *  **** ** ** *
*  ****  * *  *  ***     ** *  **** ******* *  ** * ** *  ** *  *     * * * * of %.2fx^2 + %.2fx + %.2f = 0 are real and same\n",a,b,c);
 *  *** **   * *         ****  *   ** *  *    ***   *    **** **** *  = x2 = %.2f",x1);
 ***    * * * * *  **  *****
 * **** *      * ** *    * ** ** if(D>0)
 ** * *********     * **** 
* * *  *****    * ** ***   * * * * * * **  * * *    *****    * *   ** of %.2fx^2 + %.2fx + %.2f = 0 are complex and  * **  *    ** ****
*     * * ****    * * * **    * ** *  *        * * *** ******  = %.2f\n",x1);
*   *  **  **  * *   ****   **   *       ** *  *  * *** *    ***   * *  = %.2f",x2);
 *  *    * ** ** ***   *  *  
    ***   * *  **** **** *** * if(D<0)
 *  ***** *  *   **  ****   ** *
* ** *  ******  * *   **  *  **  **   *** * *  ***  ** *****  *  ** *****   of %.2fx^2 + %.2fx + %.2f = 0 are complex and different\n",a,b,c);
*   **  * **  *  *****  * *  * *** * * *** ** ** -b/(2*a);
 * **  ******* * * * *  **    *** ** * **** ****       ****** ** ***
*    **   * **  *   *    **** *  *  ***  *****  ** ** *    *  * ** = %.2f+%.2fi\n",r,i);
* * **  *   *  *    ****   * *  *** *   *  *   * * * * *   *    = %.2f-%.2fi",r,i);
 *      ** *   ***    *      
}

Comments

prog.c: In function 'main':
prog.c:6:5: warning: implicit declaration of function 'scanf' [-Wimplicit-function-declaration]
     scanf("%f%f%f",&a,&b,&c);
     ^~~~~
prog.c:6:5: warning: incompatible implicit declaration of built-in function 'scanf'
prog.c:6:5: note: include '<stdio.h>' or provide a declaration of 'scanf'
prog.c:12:9: warning: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
         printf("Roots of %.2fx^2 + %.2fx + %.2f = 0 are real and same\n",a,b,c);
         ^~~~~~
prog.c:12:9: warning: incompatible implicit declaration of built-in function 'printf'
prog.c:12:9: note: include '<stdio.h>' or provide a declaration of 'printf'
prog.c:17:9: warning: incompatible implicit declaration of built-in function 'printf'
         printf("Roots of %.2fx^2 + %.2fx + %.2f = 0 are complex and different\n",a,b,c);
         ^~~~~~
prog.c:17:9: note: include '<stdio.h>' or provide a declaration of 'printf'
prog.c:23:9: warning: incompatible implicit declaration of built-in function 'printf'
         printf("Roots of %.2fx^2 + %.2fx + %.2f = 0 are complex and different\n",a,b,c);
         ^~~~~~
prog.c:23:9: note: include '<stdio.h>' or provide a declaration of 'printf'

Answer 5

Hidden content!
   *       ***** * ** **
int main()
{
***   * *** ***  ***    **  ** *** a,b,c,D;
***    * *****      ** *     ** x1,x2,r,i;
*******      ***      **  *  *   *******  **  *  ****** **** * *     *
**  * *  *  ** * * **    * * *    **   **
*    ** **  * *  *  * **  *  **   * ****  
****  * ** *  * * ****** ****     **   *
 *    * ** *  ** * * **  ** * ****
*** ** *  *    ** **** *  *  
*** *  ** *   *   * *** ***** * **** **   ****  * **  *** **** **    * *  of %.2fx^2 + %.2fx + %.2f = 0 are real and same\n",a,b,c);
    *  **** * ********  *    * **  *   ** * *  * * *   *   ** **** *  = x2 = %.2f",x1);
  **  *  * * **  * ***  * ****
** *   * * ****** *   *  ** * *   if(D>0)
  *     * * *       * **     *
*  ** *  * ** *  ** **   ***   * ***  * *    *** ** *  ***   ***  of %.2fx^2 + %.2fx + %.2f = 0 are complex and   *** *  **   *   
** * * *  *    *  * * * *  *   *  *   ***   *  * * *   *   = %.2f\n",x1);
 * *  **  *** * * ** *** *  *   ***  * ***  *  ** * *  ** *  *    *   ** = %.2f",x2);
 * *   * *  **  **    * *  *  *
 *  *  *   *** **** *        if(D<0)
**   ******  **  *  **   *  *
 ****  ** * * *** * * *  *   **  *** *  ** * ********* ** *     * * *   of %.2fx^2 + %.2fx + %.2f = 0 are complex and different\n",a,b,c);
  **  * ****  *** * * *  *  * *   *    *   * *  *** *  *  ** * -b/(2*a);
*   **** ***  * *   ****  *******       **** **  **  * *    ***  
**    *   **  ** ** *** *  ***  **   * * *** *  * *** * ** ***  * = %.2f+%.2fi\n",r,i);
 * *  *** *  *  ** *   ** * *** **** *    ** *   *   **   * = %.2f-%.2fi",r,i);
  **     ** ***  **   ****   *
}

Comments

prog.c: In function 'main':
prog.c:8:12: warning: implicit declaration of function 'sqrt' [-Wimplicit-function-declaration]
     x1=(-b+sqrt(D))/(2*a);
            ^~~~
prog.c:8:12: warning: incompatible implicit declaration of built-in function 'sqrt'
prog.c:8:12: note: include '<math.h>' or provide a declaration of 'sqrt'

Answer 6

Hidden content!
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
int main()
{
  * *    ****  ** ******  a,b,c,d,x1,x2;
 ***  **   * * * * *  ** * **** **  ** *      *** **  **  **  ** ****  *  *   *** 
** *** * *  * ***** *   **  **   * **
***** ** * ** ******   * * * ** ***  *** 
* **    *   ***  *  * **  ***    ***
  *****  * * **      ******* **    
*  *** * *  ***  ** ** *  ** **
*   ** ***   **     **  **  * **  * *  ** * **   **   **  *   **  * *   * *  of %.2fx^2 + %.2fx + %.2f = 0 are real and ***  *  **** *** * **
  *****    * *  ****  **   ** *** * ****    ****** * *****  * = %.2f\n",x1);
* *  *      *** ** * *    **  *****    *  *  * *  **  *  *    ***  * ***  = %.2f",x2);
*  **   **    ** ***    * 
* ** *   ** *   *** ** ****  * if(d==0)
* ** *  ** **** ** *       *   **
** *** *  * * *  * * ***** **  *** **  *  *  * * ***  ***** *     **** of %.2fx^2 + %.2fx + %.2f = 0 are real and same\n",a,b,c);
***  *** ******  * ****  ***  ***   * * * * *   ** * * * * ** *** = x2 = %.2f",x1);
*****  *  **  * *  **   * ** * 
   * *** * * **  ***    *   **
* ** ** ***   * **  ****  
  * *  *         * *  *****    ****** * * * *** *   * *  ***    *** of %.2fx^2 + %.2fx + %.2f = 0 are complex and  * *  **   * **  
   **   *  *** **   ***   ****  *    * ***  **  *   * **    *    =  * *******  *** *** ***  ** *  ***  **
**        **  *  ******       *  * ** * * * ***   *  **   *  * = * * *  ****  ******  *   * * * 
** *** *   *     ****    **** * 
* *****  **  *  **   ****** * 0;
}

Comments

Case 0: Correct output
Case 1: Correct output
Case 2: Correct output
Case 3: Correct output

Answer 7

Hidden content!
#include <stdio.h>
#include <stdlib.h>
#include <math.h>

int main()
{
 *  *  **   ************ * *  a,b,c,d,x1,x2;
* ****  *** *  ** **** ***  * ****  *       ***  ** * *** *    * * *** 
 * **  **** *****      * ***** **  *
   ** *  **   *** * ***  ** ******  = (-b + sqrt(d))/(2*a);
** * *****  **  ** ***   * = (-b - sqrt(d))/(2*a);
**    **  *     **** ** *    * 
* ***    * *** *   *  ** *   * * *   * ***   *  *  *****  *** ***** *** *  of %.2fx^2 + %.2fx + %.2f = 0 are real and different\n",a,b,c);
  *  **  ****   **      **** ***  **  **  **  *****   ****    ** ****** *  ****  *  **  * * *  * **  * *  * ***   *   **  *    ** **     *  *** * * ** **   ** ***  ** *      ** **   *  ***    * * *       *   ***       ***  = %.2f\n",x1);
* **  * *    *  ** ***   *  *  *  ****    *  * ****     ** * ***   ** *  * * **   *   *    ** **  ** *  * *  * * ***    *    ** *****     *   **** **** * * ** **  ****** *     * * ** ** * **  * *  * * *****  * * ** * ** *   **  * ****   *** ** * = %.2f",x2);}
  * *** *  *  *** **   **  if(d==0)
**   *  *   * * *   *****  ***    *      **  
****  *   **    **   * * ***    *  *  **** * *  * ** * ** * *        **** * *  * * *** of %.2fx^2 + %.2fx + %.2f = 0 are real and same\n",a,b,c);
     ****  * *    *  * *   * * **   * * *      *  * *    * *  * ** *   *** * ** * *** *  * **     *****    ***    ******* *  ****** *      *  * * ** = x2 = %.2f",x1);}
* * *** * **   ** *  ** * * 
**** *    *   *   ****** *** ** ***     * ***         * **  ** *  * of %.2fx^2 + %.2fx + %.2f = 0 are complex and different\n",a,b,c);
* * ****   * * ***   *** ****  ***  * *   * ***  *   **** ** * * ***  = ** ** *  **  ** * *  *** **** *  * 
*   * **  **  ***  * * * ****   *  **   ********* **   **  *  *  = ***   ***    ** ***** * *  
    *      **    *  ****** *** * 0;
}

Comments

Case 0: Correct output
Case 1: Correct output
Case 2: Correct output
Case 3: Correct output

Answer 8

Hidden content!
#include **  *  * ** **
#include * * ******* ** 

int main()

{
 *  * **   *    **  ***  *   ****  ***    ***
 **  ** *  * *  *** * * ** **  **** **** * %f   *** ** * **  *   *** * * *  **  *

***  **   * ** ***** **   * **   ** 
  * * **    *    **** ** *   + sqrt(D))/(2*a);
* *** * * *     * **   **   **** -    *  ** *
* * **** *** ** **   **   *      * 
**  ***** * *    ** ********  *     * * * *** 

**  *   ** **  *    * ** (D==0)
   ** *   * *** ***    **** * 
**   *  *  *    *********  *   *  *   **  * *   **** * * **   **   * *  of %.2fx^2 + %.2fx + %.2f = 0 are real and same\nx1 = x2 =   *** ****  *    
* *   ** *    *  * * *  * 
    *  ********    *   * *   if (D>0)
* *** **   ***** *  * ***   **
*  * * **  **    * * ** * **   ** * *   ** *   ****    *  *** *    *  of %.2fx^2 + %.2fx + %.2f = 0 are real and different\nx1 = %.2f\nx2 = *  **    ** * *   
**  **** ** *  * *  ** *  **
    ** ***********  **   **
* ***   * *  **    **   **
 ** ***   ***** ** * ** *  **  *       * *** **  ***      *  *  * of %.2fx^2 + %.2fx + %.2f = 0 are complex and different\nx1 = %.2f+%.2fi\nx2 =  ***  ****  ****  *** *** *  
 * * ** *  * * ***** * * *

** ****     **** *     *  ***  * 0;

}

Comments

Case 0: Correct output
Case 1: Correct output
Case 2: Correct output
Case 3: Correct output

Answer 9

Hidden content!
#include      * ***  * **
#include ***  * **  * ***
int main(void)
{
float a,b,c, D, x1, x2,i;
*  * *  ** **  *    *  * * * *   **  * * %f * ***    &a, &b, &c);
  *  * ***  **  **** **  * ***  *  
***   * *   *     ** ** *  (D>0)
*  * * *******     * *     ** 
*     *     * *****       *   **  *  **  * **   * * ** *  ** *  ** ** **
  * * **    *  *    ** *    *  * * * ****    *   ***   **** * *      

** *  ***  *    *     ***  **   ***** *   *****   * * ** ***    ** *   **     *  * **   of %.2fx^2 + %.2fx + %.2f = 0 are real and **  ****** = %.2f\nx2 =  **  *** ** **  *
  *   ****** *** *** **
 ** *      **** *** ** * **  *** if (D==0)
 * *   **   *    ****  ** 
**** ****** ****  *** *    * * *   *     ***  ******* **** **  
   *  * *  ********     **  * *  *    * ** ** ** *  *    ** * *   **  **   of %.2fx^2 + %.2fx + %.2f = 0 are real and same\nx1 = x2 = *  *   *    *** *  
 * **   * *  *      *** *** *  
*   *    * *  ** *  * **   * ** 
*** ****  * *** * **       *
*** * ****** *** ** **     ** *     x1=x2 = -b/(2*a);
  ***   ********  * ** *   * *   ***  * **   * * * **    * * **** 
* * * *** ** **   ****  * *  **      *   **  * ****     *  ***  ** * *  of %.2fx^2 + %.2fx + %.2f = 0 are complex and * * ** * = ****** * * = * * ** *** *  *    *   * x2,i);
* *   **  *** *****  * ** 



 **  * *    *    * * * **  *   0;
}

Comments

prog.c: In function 'main':
prog.c:10:16: warning: implicit declaration of function 'sqrt' [-Wimplicit-function-declaration]
         x1=(-b+sqrt(D))/(2*a);
                ^~~~
prog.c:10:16: warning: incompatible implicit declaration of built-in function 'sqrt'
prog.c:10:16: note: include '<math.h>' or provide a declaration of 'sqrt'

---

Case 0: Correct output
Case 1: Wrong output
Case 2: Wrong output
Case 3: Wrong output

---

Case 0: Correct output
Case 1: Correct output
Case 2: Wrong output
Case 3: Correct output

---

Case 0: Correct output
Case 1: Correct output
Case 2: Wrong output
Case 3: Correct output

---

prog.c: In function 'main':
prog.c:21:5: error: expected ';' before '{' token
     {
     ^

---

Case 0: Correct output
Case 1: Correct output
Case 2: Wrong output
Case 3: Correct output

---

Case 0: Correct output
Case 1: Correct output
Case 2: Wrong output
Case 3: Correct output

---

Case 0: Correct output
Case 1: Correct output
Case 2: Correct output
Case 3: Correct output

Answer 10

Hidden content!
#include  *    * * ** 
#include  ** ** ** *  * *  

int main()
{
  *   * *   ** *** *   * *** * **   a, b, c,  * ***** ** x1,x2, realPart, *     * 


 * ***  *  *** *   ***    * * *  *** *  %lf * * *   *   * *  *  * &b, &c);


 **   *   *    *** ***********    = b*b-4*a*c;

   * *   * ***  * *  * *  condition for real and different roots


  **** **   * ***   *    ****** *** *   for real and equal roots
    * **    *   *  ****          *     (determinant == 0)
** ** * * **  *   * *   * 
**** *** * *** *** **  **  ***  **   *       ***** * *  *** = x2 = -b/(2*a);
 *** **    ** * * **  *  **  * **** *** **    ****    ** ******    ** of %.2fx^2 + %.2fx + %.2f = 0 are real and   * * ****   a,b,c);
 ** * *    *** ***** ***  * * * **  ** * * *       ***    *   ** = x2 =    *  * **  x1);
* * *      ** * *  *  

*  *  ****  * *  *  * ******* **   *** *   if (determinant > 0)
* *** ** *  * *   * *  * 
**  *      * ***** * *  sqrt() function returns square root
 **  ******* *********       * ** *  *  **  * * **   * = **     * *   *  *    
  *  **   * * *  ** ***   ********   * * * * *  *   *  * = **  ***   *   *    * *

 **  *     ****  *****    * **      ** ***  **  **    *  *  *  of %.2fx^2 + %.2fx + %.2f = 0 are real and * * ** *    * ********
   * **  ** * ** *  *     ** ***  * *  *  * *  * ** ** ****  * * * =  * * * ******  x1);
 * *****     * ***   *** *    ** ** *  *  *  *     * ******  **     **  **  * = ****   * * x2);
**  * * *        *** *****    ** if roots are not real
*  *  ******** **** ****** 
* ****  *  ****   ***   **
 * * * * ** ***   *  *** * * *   ****  *  ** * * * *** = -b/(2*a);
 *** *  * ** * ****       **   * ** *   *       * *  * * * * **** * =  *  *  *** *** *
    **    ** * ** *** *    *    ***  ***** * *  ***   *  *     of %.2fx^2 + %.2fx + %.2f = 0 are complex and  *****  **  ** a,b,c);
       * **** * ** * **   *    *** **** ** * *******   *      *  = *** * * *   ** realPart, ** * * *  **
* *  *  * *** ** ** ***** **  * *  ** *  **** *    * *   * ** **** ** =   **    *   realPart,    *  *** *
******   *** ** * ** *  

  * * ********** ** **   ** *   *  0;
}

Comments

Case 0: Correct output
Case 1: Correct output
Case 2: Correct output
Case 3: Correct output