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