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

0 like 1 dislike
14.8k 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 | 14.8k 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 * *** *  * * * *****     **  ** *
** ** **    ** ****** *** = (b*b-4*a*c);
*** ** **   * * ****** *    **   * = (-b + sqrt(D))/(2*a);
***    ** *   **  *  *  ** = (-b - sqrt(D))/(2*a);
 ***** ** ** ** **** * * * **  ** *
   ** * ** * * * *  **  * * * 
*      * *  *   * ***     *  * **** *  * *** **   * * = -b/(2*a);
 * ****  ****    *   ****** * **  ** *  * ***     *  **     =sqrt(-D)/(2*a);
* *    *  ***** *  ***** *  *  * **  *    **    ***   ** * ****     of %.2fx^2 + %.2fx + %.2f = 0 are complex and   **  *  **** ** 
* * *    ** ***  **  ****    *      * * ***** * *   * ***  *  * = -%.2f+%.2fi\n", realPart,imaginaryPart);
   * * ***** * * * * **     * *  * ** ***  *       *   ** *  * *  * = -%.2f+%.2fi", **** *  * **
 *  **** *  * ** **  ****  
**  * ** * * *** **   *** ***  if(D == 0)
* ******  *  *  ** *    *

****  **    *   *  ***** *     **   ***  *  ** **** ** ***  ***** of %.2fx^2 + %.2fx + %.2f = 0 are real and *******   *** 
  *  *   ** *  *  ***     *  * **  *   * * *     *****  *    *  *** = x2 = %.2f", x1);
*   **    **  *  ******  **  * ***
*  **********    * **** *  *
  * **** * *     *  *** *** 
 *  ***  * *  ** * *  * ****  **   ****    *    *     ****  **   *  of %.2fx^2 + %.2fx + %.2f = 0 are real and * * * *  **** * 
 * * *  *  *  *   *  * * ** ***  * ******     ******* * *  **  *** = %.2f\n", x1);
*  ***** * *** *   **  ** * * * * **  ** **      * ***  * *   ***** = %.2f", x2);
****** **   *  * * * *    
     ****  * *******   * *  **** 0;

}
answered by (-281 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
/tmp/ccgUqSsU.o: In function `main':
prog.c:(.text+0x87): undefined reference to `sqrt'
prog.c:(.text+0xd5): undefined reference to `sqrt'
prog.c:(.text+0x14c): undefined reference to `sqrt'
collect2: error: ld returned 1 exit status
commented by (4.3k points)
0 0
-----------Re-judge-----------
Case 0: Wrong output
Case 1: Wrong output
Case 2: Wrong output
Case 3: Wrong output
commented by (4.3k points)
0 0
-----------Re-judge-----------
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    * ****  ***   *
#include <math.h>
int main()
{
*  **  *    * **  *   **   ** a,b,c,x,y,d;
 ****  * * **  *****  * * *  *  *  ***  *   %f   *** ****   * * *  *     * 
*****  * * *  * * * *  * * *** 
*     *  * *** *   * *   *      ** **  *  
* **  *** * **** **** * **********     
    *     ***  * *    *   ***  (d>0){
* *   *  ** ***   * **** ** *  *     **** of %.2fx^2 + %.2fx + %.2f = 0 are real and *  *  * *   * * *
    *   * **  *  *****  * *   *   ***       = %.2f\nx2 = %.2f",x,y);
   **** * * * ** * **     ** * 
***  *** * ** **** * **** *   if (d==0){
****    **** * ****    * * * ****  ***    of %.2fx^2 + %.2fx + %.2f = 0 are real and  * *   * ******  
* *  ** ********* * * *** *   *  *   ** * *  = x2 = %.2f",x);
 * *** *  **   **  * * *
***    * * * * ***    * *
  *  ** *    ** *    *    * ** * *  *
***    * ***  * * *  ** ** ***     *  of %.2fx^2 + %.2fx + %.2f = 0 are complex and ***   ***  *  * 
 ** **** *    *  *   ***       ** *  *
   *   * **** ** *      *  **  **  * = * *** ***  **** 
  * * **       ** *    **     * ***     ** = *   *  ********** * *
 *       *  *   ****    *     *

 ***    **  *  ** *   *   * 0;
}
answered by (54 points)
0 0
/tmp/cc8k7Xv8.o: In function `main':
prog.c:(.text+0x87): undefined reference to `sqrt'
prog.c:(.text+0xd5): undefined reference to `sqrt'
prog.c:(.text+0x21f): undefined reference to `sqrt'
collect2: error: ld returned 1 exit status
commented by (4.3k points)
0 0
-----------Re-judge-----------
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!
#include * *  *** ****  ** 
    *** ****  * *  * ***

int main()
{
  *  *  **   ***** *   * *  * * a, b, c, D,      *  ** realPart, ****  *  *  

* * ****  ** * *** *  * ** ***  * *** * %lf **** **** *       * * * ** * 

* *** ***   * **   ***  ***  * * = **  *  

    **      *   * **  ******    (D > 0)
 ********* ********  * *   *  
***  * **   *** *    * *** **  ** * * ** *  *  *  ** *** = *   ***   ** 
*  **** *   ** **   * ** *   **  * **  * ** ** *  * ** **  =   * *    * ** 

   * * * *   *   ****   ***    *  *   *   * * *  ***  ***   *** * ** **  of %.2lfx^2 + %.2lfx + %.2lf = 0 are real and      *    = %.2lf\nx2 =      ***  *  **  *    b, c, root1, root2);

 ******  *  **  * *  **    **

**** * **    * ****** * **    * if (D == 0)
 * *  *  *   *  * ***
 ** * *** * **   **** * ** *** **  ** * * ** ***  **  = root2 = -b/(2*a);

***  *     ** * * *    **   * *  ***    ** *  ****  *   ***** *      of %.2lfx^2 + %.2lfx + %.2lf = 0 are real and same\nx1 = x2 =   * **** *    a, b, c, root1);
*   **  **     * *     *  

*  ** **  *     ** * *** **  ***  
* *   ***  ** *  * ******* 
*  *    ****  *  **    * * *** ** ******  **     * *   *   * * = -b/(2*a);
   *** *****    ***  * * *****  ** *    *****  **  *****     = *  **** *

  **   *  * ***  *   * * *  **  *  *    ***  *     * * * * ***   * * of %.2lfx^2 + %.2lfx + %.2lf = 0 are complex and  *   *  *  =  **** * * =    *   ***   a, b, c, realPart, ******   * realPart, * ** ****
  *****  *  *    ***** * *   

 ** * ***** * ***   ** * *   *     **   ** *   *   *****
 *  *    *  ** *     *** **   * **  **  0;
}
answered by (5.2k points)
0 0
/tmp/ccibyL4w.o: In function `main':
prog.c:(.text+0x89): undefined reference to `sqrt'
prog.c:(.text+0xd4): undefined reference to `sqrt'
prog.c:(.text+0x1fc): undefined reference to `sqrt'
collect2: error: ld returned 1 exit status
commented by (4.3k points)
0 0
-----------Re-judge-----------
Case 0: Wrong output
Case 1: Wrong output
Case 2: Wrong output
Case 3: Wrong output
commented by (4.3k points)
0 0
/tmp/ccfjcMIR.o: In function `main':
prog.c:(.text+0x89): undefined reference to `sqrt'
prog.c:(.text+0xd4): undefined reference to `sqrt'
prog.c:(.text+0x1fc): undefined reference to `sqrt'
collect2: error: ld returned 1 exit status
commented by (4.3k points)
0 0
-----------Re-judge-----------
Case 0: Wrong output
Case 1: Wrong output
Case 2: Wrong output
Case 3: Wrong output
commented by (4.3k points)
0 0
-----------Re-judge-----------
Case 0: Correct output
Case 1: Correct output
Case 2: Correct output
Case 3: Correct output
commented by (4.3k points)
1 like 0 dislike 
Hidden content!
#include <stdio.h>
#include <math.h>

int main()

{
   * * *****    * *  ****** *   * **** * **  *** **     *  *

 * ** ** *  *  * *  *   * **  *   ** ***   %2f ** * ******    **     ** *  *** 
      **     *     ** *   ** = (b*b-4*a*c);
   **** **** * * *      = (-b + sqrt(D))/(2*a);
*   ** **    **  *         = (-b - sqrt(D))/(2*a);
* *   ***  * **** **   * **  ** = -b/(2*a);
*    *     ***  *    *** ***   *   ** ** =sqrt(-D)/(2*a);

* **   *  ** *  *  *** ****  (D==0)
   *  ** ** *  * *   ** * ***
** *   ***  **  * ** ****  * *** ******* ****  ****  ** * *** **  of %.2fx^2 + %.2fx + %.2f = 0 are real and     * ** *  ** **
      **   * **   *** *** ********     *     * * *****  * *** * ** * = x2 = %.2f",x);
    * ***  *** ** * ** *  
* *   * * *** *  **  *** *  ** if (D>0)
 * ****** * * *   ***  *  *  
**   ***    *  **   *      *** **  *** *  *   ** *  * * *  *******    of %.2fx^2 + %.2fx + %.2f = 0 are real and  * *    *   **   ***
**** ** ***** * *  * * ***  *** *  **   * *   ******     * * * ***  = %.2f\n",x);
***  *  * ** * * * * * ***   ****   ***  ***  *  ****  *** ** ** * = %.2f",xx);
**   *   *** *   **** *    *
  ** *   ****    *** *   *  *****  
  * *  ** *  *     *  ** ***** 
   *  * **      ***  * *      *   ***  ** * *  * ** *****   * * *     of %.2fx^2 + %.2fx + %.2f = 0 are complex and  *****  *     **  
*   *    ** * *** *   * ****   * *   *  * *    * **  ** **** *  = *** * *   * *    **  ****   *****  *
 *   ***   * *  * **   *   *** *     *** **  ** * * * * * ***** * *  ** =  **  **  * **   ***   *  ***
 ** **  **  *  ** *  **   **  *

* *      *  *** *****    *  * * 0;

}
answered by (-249 points)
0 0
/tmp/ccwpNp77.o: In function `main':
prog.c:(.text+0x87): undefined reference to `sqrt'
prog.c:(.text+0xd5): undefined reference to `sqrt'
prog.c:(.text+0x13e): undefined reference to `sqrt'
collect2: error: ld returned 1 exit status
commented by (4.3k points)
0 0
-----------Re-judge-----------
Case 0: Wrong output
Case 1: Wrong output
Case 2: Wrong output
Case 3: Wrong output
commented by (4.3k points)
0 0
/tmp/ccWys99e.o: In function `main':
prog.c:(.text+0x87): undefined reference to `sqrt'
prog.c:(.text+0xd5): undefined reference to `sqrt'
prog.c:(.text+0x13e): undefined reference to `sqrt'
collect2: error: ld returned 1 exit status
commented by (4.3k points)
0 0
-----------Re-judge-----------
Case 0: Wrong output
Case 1: Wrong output
Case 2: Wrong output
Case 3: Wrong output
commented by (4.3k points)
0 0
-----------Re-judge-----------
Case 0: Correct output
Case 1: Correct output
Case 2: Correct output
Case 3: Correct output
commented by (4.3k points)
1 like 0 dislike 
Hidden content!
**   *** * ****    * 
 **  *  *   **** 
int main(){
***  **  * *  * *   **    ***       ** a,b,c;
   ** *****  * ***** *** D;
 ***  *  ****   * ***  ** * *****   ** %lf   **** * * * **  ***  *    * *  **  *
 *****   *  *****      **** ** ***** * - 4*a*c ;

    ** *    *    **  ******  ***  * **** of %.2fx^2 + %.2fx + %.2f = 0 *   ** **  *

*  ***   *   **  ***** ***  **    
* ***  **  *** *  *** * *   *  * ***********    *** * *  **  *     * complex and ** * ******   *  
******  *****  *    * ** ** * ***  ***** * *     * **  * * =  * *       *  * *  (-b) / (2*a) ), sqrt(-D) / (2*a) );
 * *****  ***   * * * *    **** **  *  *** ***    **  *   ** **   *    =  ***   *   ** *  (-b) / (2*a) ), sqrt(-D) / (2*a) );
 *  ** *    ****      * * *** **
*  *  * ****   ***    *  ** if(D==0){
  ** * ** * *    ****   * *  **  ** * *** ***  ** * *** * *    **  *   * * real and same\n");
**** ****      *** * **** ***   *    * *** *       *** * ** **  * ** *** = x2 = %.2f",( (-b) / (2*a) ) );
 *****    *  ***  * * * *  ** *
**  ** ******   **  * * *  *   ***
  *** *  * ** **  * ***       ***     **  ** * **  *  *** *    **** real and   * * ****  * *** 
**  *** ****     * ******* *    *****    ** * ** *  *  * ** ****** = %.2f\n",( ((-b) + sqrt(D)) / (2*a) ) );
 ****  **  **  * **  *  *  ** *  *     **   *   * ****   *    = %.2f", ( ((-b) - sqrt(D)) / (2*a) ) );
****   *      *** **  ***

*  **   **** **  *     * **  *   0;
}
answered by (-116 points)
0 0
/tmp/ccpv8G38.o: In function `main':
prog.c:(.text+0x51): undefined reference to `pow'
prog.c:(.text+0xdd): undefined reference to `sqrt'
prog.c:(.text+0x13f): undefined reference to `sqrt'
prog.c:(.text+0x213): undefined reference to `sqrt'
prog.c:(.text+0x26a): undefined reference to `sqrt'
collect2: error: ld returned 1 exit status
commented by (4.3k points)
0 0
-----------Re-judge-----------
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!
#include <stdio.h>
#include <math.h>

int main()

{
   ***   ** * ***  *** ****     ** ****   *     * * *  *

  *  * *  ***  * *   * *  ***  *   ********  *    %2f    ** ****  *  ****  * * *  
*      **** **  * * **      = (b*b-4*a*c);
*    **  *  ***  * ***  * *  * = (-b + sqrt(D))/(2*a);
* * *  **** ** *  ** **    = (-b - sqrt(D))/(2*a);
  ** ** * * *** ** *** ** ** **      = -b/(2*a);
 *     *  **  * *  * * * *    *  ***    =sqrt(-D)/(2*a);

*** * * *****  **  *  **    (D==0)
  ** ***   **  **  ***** ** 
 ****  * **  * *       *  *     *** ** ** **    * ****  *** ** * *  *  *** of %.2fx^2 + %.2fx + %.2f = 0 are real and  **    *   *** 
 *   ** ********* **** ******  * * * * **   ***  *     *** *  ** *  = x2 = %.2f",x);
*   **   *    ***   **
  **  *******  * * ** **   * if (D>0)
***  **   **   *  **** *  ** * 
*  *        *       *  ** *  ** **   *  *  ***       **   * * * * of %.2fx^2 + %.2fx + %.2f = 0 are real and  ** * *  ** ** *
  * ***      **  *  * *       *******  *  ***  * ***       *** * *  = %.2f\n",x);
 * *  *** ***   **** * ** *  *  *   ***  * *  ** *  * *    ** = %.2f",xx);
 *  **** ******* ** *   ***   
    * **  *****  *  **  *    
*  **** **   ** **   ***  *  * *
** *   *  **** ****      **  *  * *****   *  *** ***   *  * **   ******** of %.2fx^2 + %.2fx + %.2f = 0 are complex and   *  **** ** *  **  * 
*    *  * * ***** *  ** **  ** **   *  * *       * *  ** *   =   ******  ****    *** ***  * ***
  *   ** * *** ** * *  ****  * * ****  ** *  ** **  *  * **** *  ** = *   * * **  *  ** *  ****   
  **** **  *      * * * * 

 ***   *   *    *    ****  *  *    0;

}
answered by (-249 points)
0 0
/tmp/cckgLAYq.o: In function `main':
prog.c:(.text+0x87): undefined reference to `sqrt'
prog.c:(.text+0xd5): undefined reference to `sqrt'
prog.c:(.text+0x13e): undefined reference to `sqrt'
collect2: error: ld returned 1 exit status
commented by (4.3k points)
Page:
Welcome to Peer-Interaction Programming Learning System (PIPLS) LTLab, National DongHwa University
English 中文 Tiếng Việt
IP:172.70.50.50
©2016-2025

No related questions found

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