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

0 like 1 dislike
15.5k 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 | 15.5k 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:172.69.130.114
©2016-2025

No related questions found

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