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