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

0 like 1 dislike
8.6k 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 | 8.6k 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:172.71.1.149
©2016-2025

No related questions found

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