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