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:172.69.17.117
©2016-2025

No related questions found

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