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

0 like 1 dislike
7.9k 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 | 7.9k 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:172.70.126.200
©2016-2025

No related questions found

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