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

0 like 1 dislike
15k 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 | 15k 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:172.69.214.204
©2016-2025

No related questions found

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