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

0 like 1 dislike
16k 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 | 16k 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:172.70.126.17
©2016-2026

No related questions found

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