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