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:172.71.120.76
©2016-2026

No related questions found

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