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

0 like 1 dislike
7.6k 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 | 7.6k 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:172.70.131.161
©2016-2025

No related questions found

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