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