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