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