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