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