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