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