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