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:104.23.243.109
©2016-2026

No related questions found

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