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

0 like 1 dislike
15.3k 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 | 15.3k 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:172.69.214.205
©2016-2025

No related questions found

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