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