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

0 like 1 dislike
11.9k 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 | 11.9k 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:172.69.214.205
©2016-2025

No related questions found

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