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