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!
   **** *   **  **** *
  ***  *  ** *  * *

int main() {
* * **  * * *** * * ** *** ** * **  
******* ******  *** ***    **     * * * * %f *      **  &a, &b, *   **  **
****  *    ** *** *    ** * *  ** ***
**  **  *   ****     ***       **  *  {
* *** * * *****   * *  *  ***    *** ** *   *  * *       * ** of %.2fx^2 + %.2fx + %.2f = 0 are complex and * *   * =   * **   = * *** * *  *  a, b, c, (-b)/(2*a),  * **   *  (-b)/(2*a),  ***  ** * 
**  *** *****    * *    **  ** 
** *** *  *  *  * ** **   ** * if(d==0) {
  *****  *  *   ** ***  ** *** *  *    * **    ****  **    * * *** 
 ** *   * *** *    *  **  *  *** *** **** * * * ** *** *   **** *    of %.2fx^2 + %.2fx + %.2f = 0 are real and same\nx1 = x2 = *  **** **  a, b, c, x1);
    * **** *** * ** * * **** 
****  * *  * ****  **      **  **  *  *   * {
* **   **    ****  **    * *   *** **  ***** *  ******   ** ** *  *
      *** *  *   * *  **  ***  * * *  ** *  * ****  * *** *  *  *
**   *  * *  **** **      * *  * *** ****  *****  ** ** ** ***   ** *   of %.2fx^2 + %.2fx + %.2f = 0 are real and  *  *  = %.2f\nx2 =  *     *  a, b, c, x1, x2);
    *** *  ******* *** ** ** 
}

Comments

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

Answer 2

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

int main()
{
  ** **  **    * *       **   *    *** *    
**  **    *     ******  *   **** * %f   *  ** *  ****  *  ****  *  ** *** 
*  ****  ***  *****  *    *  *  * *
   * ***** ********  *** *** ** *   ***** *
* * *  *    *  **  ***** ****  *  *** *  **
 * ** **  *   ****  **   **  * * *  
  ** **********   ****         * *     ** **** 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 = *   ***  *** ** 
 ** **  *  * * * *  *       ****
* ***  *** ****     **  *** * * **     *** **   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 3

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

int main()
{
***** *  * ** *    * *   *       *  * ** * **
*    *  ***** *  ** ***  *  *  **** ** *  %f  * ***    *** *** ** **    **
 ** ** ******** *     **   *  * ** **
*     * ******  ***   * * **  *** *  *  
 **  *  *** ** *     * *     *** * 
 * ** **    *  *******   *    * 
* *** *****  ********* * * * ****** * *  of %.2fx^2 + %.2fx + %.2f = 0 are real and ****  * ** = %.2f\nx2 =   *  *** ***     *
 * ** * *  *  *** ***   * **  *   *
****** * ** *  *****  *  * *   **  *      of %.2fx^2 + %.2fx + %.2f = 0 are real and same\nx1 = x2 =    *  *** ***  *
*  *   *   ** *  **   * *   *  
* *   ***  *   *****  **     **  * * *   * of %.2fx^2 + %.2fx + %.2f = 0 are complex and      *** = %.2f +  ***  *  = %.2f -    ** ***     *   *******  **  **  *  *** * *** *
 **  **   *  *  * * * *    ***    0;
}

Comments

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

Answer 4

Hidden content!
#include <stdio.h>
#include <stdlib.h>
#include<math.h>
int main()
{
*    *   ** ****  ***  * * * a,b,c,x1,x2,D;
*     **** ** ** *** **   * *  *  * %f  **  ** * * *   ** *  * * * * ** 
*  * ****** ** * *      **** **** **   
*  * * *  **  * *   ******   ** *  = (-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 5

Hidden content!
#include <stdio.h>
#include <stdlib.h>
#include<math.h>
int main()
{
       *       * **  ****** ** *    a,b,c,x1,x2,D;
* ****   * *** * * ** * **  * *     * *** %f * *****  * ***    * * *
* * ** * * *  * **  **     * ***** **  *  
   * **  ***   ** *  *  * ****   = (-b + sqrt(D))/(2*a);
**** *   *  ** ****  ** *** * ****  * = (-b - sqrt(D))/(2*a);
  ** **    * **      * *   * *  **
  *** *** *  ** *  ** *  *   **   *   *   **     *  * *** 
* * * ** *  *  *  * *  ***      **  * *  * ***** * *   ***   *  *  **   * * * * *  *  * *   *  * of %.2fx^2 + %.2fx + 1.00 = 0 are real and different\n",a,b,c);
  *  ** **    **  ** * **  **  *   ***   **  **  * *   ** *   * *** *  **** **    *  ** ** *  ***  = %.2f\n",x1);
 **  * **** *   *    *****   *   *       * *    *  *   ** *  ********   ** * *    **   ** * **  = %.2f",x2);
 ** *  *** *      * * *  *  * ** ***   ** * * ** * **  * 
 ** ***   * *   *  ** *   * if(D==0)
* **  **** * ****** * **** * *  **       *  * * *
***   ** * * ***    * *    *  *    *  ****         *  *  *  *     *** **  **** * **  * **  of %.2fx^2 + %.2fx + 1.00 = 0 are real and same\n",a,b,c);
  ** * **    *  *  *    *  * * **** * * *   *   * * *** * * * *** *  * *   * ** ** *  *    *  * *   = x2 = %.2f",x1);
*     ** * ** * **  ** *   *  * ****** ** *** **  **
*  *****  ***   * *  **   **     *
 **    *** *** **  ****  * * * *** ** **   ***  * ** *  *  *
  **** *     * ******* **   * * **   **** * * * ** ****   ****  ***   **  *   *** *    *  *  * * of %.2fx^2 + %.2fx + 1.00 = 0 are complex and different\n",a,b,c);
* *         *    * *    *******  * ****  ** **  * **    *  ** **** ** **** * ******   **  * *  =   *  ** *** ** ****   ***  * *
 ******** ****  *******  *  ***  ** **  *  ***  *  * * ** * * * *    * ** *    *  **  * *   *   = *  ** *  *   ** ** ***** ** 
 *  *** * ** *  ***    ** *  * **  *   *    **   *   
      ***  ** *** **  ****   * ** 0;
}

Comments

prog.c: In function 'main':
prog.c:13:20: warning: too many arguments for format [-Wformat-extra-args]
             printf("Roots of %.2fx^2 + %.2fx + 1.00 = 0 are real and different\n",a,b,c);
                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
prog.c:19:20: warning: too many arguments for format [-Wformat-extra-args]
             printf("Roots of %.2fx^2 + %.2fx + 1.00 = 0 are real and same\n",a,b,c);
                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
prog.c:24:20: warning: too many arguments for format [-Wformat-extra-args]
             printf("Roots of %.2fx^2 + %.2fx + 1.00 = 0 are complex and different\n",a,b,c);
                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Answer 6

Hidden content!
*  * ** *  * *    * 
***  * *** * **    **** 
int main()
{
  * * **  *  *     *** * *     a,b,c,D = 0,x1 = 0,x2 = 0;
**  * *  *   * *** * * ** **  ** ** *   * ****     *  ********    ***  **** 

**** *    * * ** *      ****  **     of %.2fx^2 + %.2fx +%.2f = 0 ** **  * * 
    * ***** ** **  * *  * = (b*b-4*a*c);
   ******** *  **   *******  *  (D < 0)
* * ** *    *  *  **    **   *  
 ** ****   ** *   ** **** * * ** *  * complex and    * ** ******
  ***  ****  *       *       ** ***** *  = *  * *** ** ***     * *** * * *  *  
*    *****   * **** *       *  *      ***  = *   **    *** * ** *   * * *****
*  ***** ***   *  * ****  *
**** *** * * * ***   *     (D > 0)
** * ***** *  **  ** * ** *
 *       *  **   ******* *   ** * *   * real and *     **  ****** *
 *** * * ** *    * * ** *   ** *   **     = *** *      *    * + sqrt(D))/(2*a));
*     *** **   ****** ******  *   *  = %.2f",(-b - sqrt(D))/(2*a));
 *  * ** *** **** * *** 
 **** **  **** *  *** * * (D == 0)
**   **      *****   **   
* * **  ** **  * ***   *  *  *   *  ***  *  real and same\n");
* ****** *** ** *****  * * **   * * * = x2 = %.2f",(-b + sqrt(D))/(2*a));
***  *****  * *  *  *  * 
}

Comments

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

---

your output lack of 1 space at line 8 when print out "Roots of ..."

Answer 7

Hidden content!
 *  * *  ** *   * *
  **  **** *         
int main()
{
*  *  ** *   * **** *   ** **      a,b,c,D = 0,x1 = 0,x2 = 0;
*   *****  * *   **  *  *  ***  ****  * **  ****   *** ** *** *  

* * ** * * **   *  * *  * * *** *  * *   of %.2fx^2 + %.2fx +%.2f = 0  **  *  ** *
   **    *     ***  **  ** * = (b*b-4*a*c);
      * ** ****  *  *  *** *  *  (D < 0)
 ** ***  ***** * * * *** 
  ***  * * *  *** * **  ** ** ** *** *  * complex and ** **  *   **  *
*    ***  *  **** ** *     **    *** ***    = *** *  *  *** **  **  * *  * * *
*     *  *  ** ***** **  ** ****  * ** = ****  * **   *   *****  ** 
*    * ****  **** **  ** ** *
  ***** **  **  * ** ***   * *  (D > 0)
*     * *   **    ***  **
** ** **  *  * * **   *  **   ***  *  real and ** ** * *    ** 
***   *   * ********* * ** * *  *  * =   *  **  *****  + sqrt(D))/(2*a));
*** *  * **  ***    *  * ******* * * * = %.2f",(-b - sqrt(D))/(2*a));
** ** **   *  *  ***** *** ** 
* *    *  ******   * *  ** *    (D == 0)
**       *  ***    **   * **
  * * *  * ** * *  ** *****    ***  *     real and same\n");
  *   ** **  ****     * * ** ***  **  * = x2 = %.2f",(-b + sqrt(D))/(2*a));
    * ***      **  **** *** ** 
}

Comments

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

Answer 8

Hidden content!
***  ** *  *   * ** **
 * *  * * * * **  *** *
int main()
{
** *      **  * *****  * **     **  a,b,c,D = 0,x1 = 0,x2 = 0;
 * ** * *  * * *** * *  **   **  **  ***  **   **     **   *  *     

*** *  ** *  * **   * *  ***     **** of %.2fx^2 + %.2fx +%.2f = 0 * ** *   *
 * ********   * *  **   * * **  ** = (b*b-4*a*c);
 *   * * * ***  *    * *** (D < 0)
 ** **   ** **   ** *  * * ***
     ** * * *** * ****   ***** * *** ** **   complex and * *** * * * *     *
  * * ****   **** * *  **  ***  *  = *****   ***   ****  * *    *** * 
** * ***  *   ****   ** **   * * *  **  ** *  *  * = *     *      * **   * *  * **
 *   **  * ***  ***   *  **
 * **  *  *  ** ***** (D > 0)
*   *** ***** ***   ** ****
* *    *** *  **   * ****   *   *   *    real and  * **   * * * 
* * * *  *** *  * *** *** ****    **    *  =  *     * ***   *  + sqrt(D))/(2*a));
 ** * ** *   **  *     *** *** *  * *  = %.2f",(-b - sqrt(D))/(2*a));
 **    **  ***  *  * ****
*    *    * * ***     * *** ** (D == 0)
  * * * ***  ***  * *   * *******
   *  * ***  **  *  ** * **  * **   **    real and same\r\n");
** ****    ***  * *** ***  **  *  *   *    = x2 = %.2f",(-b + sqrt(D))/(2*a));
* *  * ** **  ** *   
}

Comments

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

Answer 9

Hidden content!
 **   * ** **  *
    *   ** *    *  *  
int main()
{
** **   * *   ******  ** * *  *   a,b,c,D = 0,x1 = 0,x2 = 0;
    *  *   ** *    ** * **   *     *  ***  **** *   * * *       * *  * ** ** **

**   * *** ****    *   ** *****   ** **     of %.2fx^2 + %.2fx +%.2f = 0  *     * **  
***** *        **  *****  *  = (b*b-4*a*c);
*   * **** * * * ***  ** * (D < 0)
 * * *     ********* ******* *
*    **        *** * * ****  * *   *   complex and  * *** *  ***
 ** * *   * * * *   *  * **  *** * ** * * * = ****  * ** *    **** ******      *
   *   **  *   * *** ***  *    ***       =   ***  *    *  *** ******     ***
*   *** * * * ** **  *  *
* *   *  ** * * *   * ** ** (D > 0)
**  * ** ** * ** * **********
* ** ** *   *   ******  *   *  * ** *** real and   ** * ***  ** 
     * ***  ** *** *       **     * * =    *      ** + sqrt(D))/(2*a));
 * * *  ****  ** ***  ***** **** ** = %.2f",(-b - sqrt(D))/(2*a));
** *     * *  ** *** *********
*   ***  **   ** *  **  *  **  (D == 0)
*  * *    * *  * ** ***  *
****   ** *    ****  *   *   **** real and same\r\n");
* * **  *  ** * *   *  ** ***     *  * = x2 = %.2f",(-b + sqrt(D))/(2*a));
  *    *   * ****  *
}

Comments

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

Answer 10

Hidden content!
*** ** ** **   * *  *
 ** *** * ** ****** *
int main()
{
 *     *   ** ** **   *   *** a,b,c,D = 0,x1 = 0,x2 = 0;
 *** ** ** *** **    *    * ***  ***   * ** **** *  **  * *  *   * ***

  * * *  *    * **** ******** ****    of %.2fx^2 + %.2fx +%.2f = 0 are",a,b,c);
            **** * * *****  = (b*b-4*a*c);
    **  *** *  * ** ** * *      = (-b + sqrt(D))/(2*a);
**   **** * ****  *    *     = (-b - sqrt(D))/(2*a);
 *      *     ** * *  *  ** (D < 0)
********   *** *** ***** 
*** * ********    * * **  ***    * *** complex and   * ***  ** ** ***
  ** * * *  * * ****  ** **** *  *****  * =     * *** ***  * **** *  *** ** *  ***
 * ** ***  **   *****   *  ****  * * *  * ***   =   **** ** ****  * * **  **  *
  * ******   *     ****   * *  **
** *   ***  ****  *  * * * (D > 0)
* **  ** *****    * * * 
* * * *    **   ***  *** *     ** ** * real and * ****  **   * *
 ***  * **   ***   * * ** * *    =  ** *** **    * **
* ***  * *   **    **  * ****  * *** * = %.2f",x2);
**  * *** ****  **   ****   **
** ** **   * **  ** *   ***  (D == 0)
*    *    *** ** ***  **     
 *** ***   **  * *       ** ** * * real and same\r\n");
* * * ****     *  ** * * *   * **  = x2 = %.2f",x1);
**** *    *  ** ****   ** *
}

Comments

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