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

0 like 1 dislike
19.7k 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 | 19.7k 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:104.23.243.108
©2016-2026

No related questions found

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