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

0 like 1 dislike
10.3k 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 | 10.3k 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:172.70.100.100
©2016-2025

No related questions found

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