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