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:172.70.178.131
©2016-2025

No related questions found

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