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