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