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

0 like 1 dislike
20k 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 | 20k 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:104.23.197.94
©2016-2026

No related questions found

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