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