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