10-26 Exercise 3: Find roots of a quadratic equation

0 like 1 dislike
17.5k views

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
[Exercise] Coding (C) - asked in Chapter 5: Selection Statements by (5.2k points)
ID: 28934 - Available when: 2017-10-26 18:00 - Due to: Unlimited
reopened by | 17.5k views
0 0
We will continue this question in few days
commented by (12.1k points)
0 0
Everything is fixed. Enjoy your time with The Judge :)
commented by (12.1k points)
0 0
ANNNNNNNNNNNNNNNNNNNNNNNNNNGRYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY
commented by (-249 points)
0 0
Your code has newline at the end sometime. You learned this lesson many times!
commented by (12.1k points)
0 0
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.
commented by (-214 points)
0 0
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
commented by (9.9k points)

56 Answers

0 like 0 dislike 
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);
  * *   ***********    *  ***  ***
}
answered
0 0
Case 0: Correct output
Case 1: Correct output
Case 2: Correct output
Case 3: Correct output
commented by (4.3k points)
0 like 0 dislike 
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;
}
answered by (-498 points)
0 0
Case 0: Correct output
Case 1: Correct output
Case 2: Correct output
Case 3: Correct output
commented by (4.3k points)
0 like 0 dislike 
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;
}
answered by (-498 points)
0 0
Case 0: Correct output
Case 1: Correct output
Case 2: Wrong output
Case 3: Correct output
commented by (4.3k points)
0 like 0 dislike 
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;
}
answered by (-258 points)
0 0
Case 0: Correct output
Case 1: Correct output
Case 2: Correct output
Case 3: Correct output
commented by (4.3k points)
0 like 0 dislike 
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;
}
answered by (-258 points)
0 0
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);
                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
commented by (4.3k points)
0 like 0 dislike 
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));
*** ***  ** *  * ***** ** 
}
answered by (-214 points)
0 0
Case 0: Wrong output
Case 1: Wrong output
Case 2: Wrong output
Case 3: Wrong output
commented by (4.3k points)
0 0
your output lack of 1 space at line 8 when print out "Roots of ..."
commented by (9.9k points)
0 like 0 dislike 
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));
* *  * * *  * *** *   **
}
answered by (-214 points)
0 0
Case 0: Wrong output
Case 1: Wrong output
Case 2: Wrong output
Case 3: Wrong output
commented by (4.3k points)
0 like 0 dislike 
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));
*****  *  ******       *
}
answered by (-214 points)
0 0
Case 0: Wrong output
Case 1: Wrong output
Case 2: Wrong output
Case 3: Wrong output
commented by (4.3k points)
0 like 0 dislike 
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));
 ***  ****  * *   *** * ** *****  
}
answered by (-214 points)
0 0
Case 0: Wrong output
Case 1: Wrong output
Case 2: Wrong output
Case 3: Wrong output
commented by (4.3k points)
0 like 0 dislike 
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);
    * ***   *    *    *****
}
answered by (-214 points)
0 0
Case 0: Wrong output
Case 1: Wrong output
Case 2: Wrong output
Case 3: Wrong output
commented by (4.3k points)
Page:
Welcome to Peer-Interaction Programming Learning System (PIPLS) LTLab, National DongHwa University
English 中文 Tiếng Việt
IP:104.23.197.94
©2016-2026

No related questions found

12,783 questions
183,442 answers
172,219 comments
4,824 users