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