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

0 like 1 dislike
15.9k 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 | 15.9k 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:172.71.254.169
©2016-2026

No related questions found

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