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