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