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