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