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