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