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