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