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

0 like 1 dislike
17.3k 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 | 17.3k 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:162.159.115.32
©2016-2026

No related questions found

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