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

Question

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

Comments

We will continue this question in few days

---

Everything is fixed. Enjoy your time with The Judge :)

---

ANNNNNNNNNNNNNNNNNNNNNNNNNNGRYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY

---

Your code has newline at the end sometime. You learned this lesson many times!

---

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.

---

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

Answer 1

Hidden content!
**  *   *   ** *   *
*  *** ** *  **   * 

int main() {
*  ** * *** * **   ***** * ** **     *   
  *   * *****  * *  **    *    *  * *    %f * * *** &a, &b,  *     * *
 * *** *    *  **** **  **      
*  ***  * **  ** ******* *  ***  *   {
 * *         **  * * ****** ** *****   *    * *     * * **  ** * *       of %.2fx^2 + %.2fx + %.2f = 0 are complex and * **  * * = *       ** ** = ** * *     ** ** a, b, c, (-b)/(2*a),   *******    (-b)/(2*a), **  *  *
  *   *****  *  ***  **       
*   * ****  *  * *** ***   **  * if(d==0) {
 *** * * ***  *****  * **  ***   ** **   *** * ** **   *** * *  *  **** **  
* *  *  * **  ** **    *   * *    *  ** ********* * **  ****  **     of %.2fx^2 + %.2fx + %.2f = 0 are real and same\nx1 = x2 =   *** ** a, b, c, x1);
  * *    ***  **** ***  ** *  
** ***  * * **    *   **  *** * *   **   * {
    **  *   ** *  * *  *   ***** * ***  ** *** * ** ** *****   ** *
 * *    **    **** *****           * * **  *** *  *  ** **  ****
 **** **  * **   *  *  **  *     * ** ***    * * *** *     *   ** **  of %.2fx^2 + %.2fx + %.2f = 0 are real and  **  **    = %.2f\nx2 = * * **  *  a, b, c, x1, x2);
*** ** ** **  * **     * *
}

Comments

Case 0: Correct output
Case 1: Correct output
Case 2: Correct output
Case 3: Correct output

Answer 2

Hidden content!
#include      *  *  *
 *  *** ***  * * * *******
#include   * **   **  * *

int main()
{
   * *  ***       ***   * *  **  *** *
      * *    *  * * ** * ** ****   ****  %f    *  **   **  ** **        *** **
 ** * *   *  *      * * **  * *
 * * ** ** ***  **  * *   * *  *  *   *
*   **   * *  *  **** *******  *  *   * *
*****  **********  * *** ***  
**  **  * * *  * *****  *    **  *      of %.2fx^2 + %.2fx + %.2f = 0 are real and   *** * *** = %.2f\nx2 = **   *        *
* ***  **** **   *  * * ***   * if(D==0)
 ***   *    ** **** *   **   ***   **  **   of %.2fx^2 + %.2fx + %.2f = 0 are real and same\nx1 = x2 = ** ****** **   ****
**  **  * * * **** *    *  ***    ***
***  **** ****** * ***  *  ***** **  **  *  **  of %.2fx^2 + %.2fx + %.2f = 0 are complex and *  **  *  =  *   *** *** =    **     *  ** ***     ** *  *** ***** *** ****   *
 *    **    * ***  ** *** **  * *  0;
}

Comments

Case 0: Correct output
Case 1: Correct output
Case 2: Correct output
Case 3: Correct output

Answer 3

Hidden content!
#include ****  ** *   **  
*   **  ***  **      
 * ****  * ** * * *  

int main()
{
 ** * * * ** * ** * ** * * * *         *  
  *   *  **    ** *  *** *   ** *   ** *  %f ***   * * * *   * * * *** **  * *
** *   ** *  * ** * **   *  *** **      * 
  *****     ** *   *   *  * ** **   * ** **  ***
***    *    * **   *  *  ****** * * * *
*   *  *  * **      * * *   * * *   * *
  **  **    *  *  *    ***   **** **      ** of %.2fx^2 + %.2fx + %.2f = 0 are real and  *****   = %.2f\nx2 = * ** *  *  *   *  * *
 **** **** **  **** **** *  ******
*****      ** ***    ** ***** *  * ***** ** *  of %.2fx^2 + %.2fx + %.2f = 0 are real and same\nx1 = x2 =   *  *  * ***
***  * ***  * *    ***   ** *** 
*  ***      * **   ***** ** **  ** ******   of %.2fx^2 + %.2fx + %.2f = 0 are complex and  ******  = %.2f +   **    * = %.2f -  ***** ** **  **  * *  *   *  ******   * * *
  *** ** * **  *  * ******  * 0;
}

Comments

Case 0: Correct output
Case 1: Correct output
Case 2: Wrong output
Case 3: Correct output

Answer 4

Hidden content!
#include <stdio.h>
#include <stdlib.h>
#include<math.h>
int main()
{
***    ** *** ***   **** * ** *  a,b,c,x1,x2,D;
* * **   *    * *** *** ***  **   **  **  %f *   **   * *   ** * *    * * *  ****
***   ***** *** *****   *  **   ** 
 *  * * *       *  * **    *  = (-b + sqrt(D))/(2*a);
 **  **   **** * *  * ** ***** * = (-b - sqrt(D))/(2*a);
     * **    * *  *          * * *** 
 ** * ****  * *  *   *   * * * ** ********** *   
    ** ***  **  ** * ******  *** ** **   * *    *** *   *   ***** *   ***** *          ***  of %.2fx^2 + %.2fx + %.2f = 0 are real and different\n",a,b,c);
*** ** *  *  ** * ***** **  ** ** **   *  ** ****  ***  * ** ** *** *  *** *   ** ***** * * **    = %.2f\n",x1);
 **    * ** * *** *** * *   *   *     * *  *  *   *** ** ***** ** *  ***    * *  *  ***   **  = %.2f",x2);
*  **** *****    **** ** *** **   *  **   *   *    **
*     ** * * * **   * * *    * * if(D==0)
*  ***  ** ** **    *** ***    *   * **  ** ** *
*   ***    ** **   * ** ***  *  * *******  ****   *     * *    * **  *   * * **  * **** * * of %.2fx^2 + %.2fx + %.2f = 0 are real and same\n",a,b,c);
 ******  ** * * **** ****  *  ***   * *    *   ***  *  ***  ***** ****     **** ** ***** = x2 = %.2f",x1);
  * *  * *   * **** * * ** *  * *  * ** *       ** ** ** 
* ***********    * *** * ***** *
**** *    ***** * *** *     **** *  * ** *      *  *   * 
   * *   ***** *** **  ***  ** ****   **  ** * *   * ***      * **** *  *   ********* ** ***  of %.2fx^2 + %.2fx + %.2f = 0 are complex and different\n",a,b,c);
   ***   *  **    ***   ** *** **  ****   * * **     *  * *  *  **   * *           * **  *** = *** *  **      * *  * * 
 **** ****    * ***** * * *** * * ** ****** *  **** *** * *  **  *  *  *  ** * * * **********   * ** = ** * ** ***   *****  * * 
    **   *****   *    ****       *    ** ****    **  **  * *
* * *   * * ****    ***** * *   0;
}

Comments

Case 0: Correct output
Case 1: Correct output
Case 2: Correct output
Case 3: Correct output

Answer 5

Hidden content!
#include <stdio.h>
#include <stdlib.h>
#include<math.h>
int main()
{
 *** * ***** *****  * ** * *  * a,b,c,x1,x2,D;
 *   ** **     ****** *    *  ***** %f  * * **   *** * * ***    * 
*****  **     *****   * ** ** * *     
 * * ***     ***    * **  = (-b + sqrt(D))/(2*a);
     * **  ** ******** ****  = (-b - sqrt(D))/(2*a);
* *  *  *    **** * * * *** *******     * *
*  * * *  * ******* *** ****   * **     *    * ***  * *
*  * ***  ******  **  * *   * * * ** *  *   *** **** ** ** *** **  * ****  **  *** *  *      ** of %.2fx^2 + %.2fx + 1.00 = 0 are real and different\n",a,b,c);
** *   *****     *** **  *    **  *******  *    *** ** ***   * **     * *  **   *   *    **  ** = %.2f\n",x1);
* **  *     * ***   *  **  ** *****  *  *      *   ** * ** *  *  * *******  **   * * **    = %.2f",x2);
****  *  *   ** * **  * *  *    **  * **** *** *  *****
*   ******* * *  *  *  * * * ** if(D==0)
 *  *  *    * ** *  *       * ** ***   *      *******      * 
 ***    * **      *****   * **      *****   **   * *  *   **   ***      ** ** ****** *   *** of %.2fx^2 + %.2fx + 1.00 = 0 are real and same\n",a,b,c);
 ** *    * ** * **  ***** * ***   *** *** ***** *   * * * * * *     *  *  ***  * *  ***  * **** *** = x2 = %.2f",x1);
** **   ** * *   *     *  *  *   *    *    * *  * * * **
* *   ******* *** ****** **   *  
 * * *  *** *   *   **  *** *    * **    *  * *  
    * * **** **   * *    ** **   ** *** * *  *  **   *  *    ****  *   *  **** *  * **    *****   ****   of %.2fx^2 + %.2fx + 1.00 = 0 are complex and different\n",a,b,c);
*     ****     *    * *** * ***  *  ***    ** *******  ***  *****  *****  * * * *   *** * * *   **    * = *  *  ** ** **  ** *  *    *   *
*   *   ** **    **  **  **  * ** **    *    ** ***  **     *  *  *  * * * * *   *       * * *     =  ***  *** *** **********  ***
  * * ***  **    *    * ****  * **** *** **  ***** ****    
 ** **  **     ***  *  ***  *    0;
}

Comments

prog.c: In function 'main':
prog.c:13:20: warning: too many arguments for format [-Wformat-extra-args]
             printf("Roots of %.2fx^2 + %.2fx + 1.00 = 0 are real and different\n",a,b,c);
                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
prog.c:19:20: warning: too many arguments for format [-Wformat-extra-args]
             printf("Roots of %.2fx^2 + %.2fx + 1.00 = 0 are real and same\n",a,b,c);
                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
prog.c:24:20: warning: too many arguments for format [-Wformat-extra-args]
             printf("Roots of %.2fx^2 + %.2fx + 1.00 = 0 are complex and different\n",a,b,c);
                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Answer 6

Hidden content!
******* * * ***   ****  **
***  ** *** *     
int main()
{
* ****** *   **   *  *   *****   a,b,c,D = 0,x1 = 0,x2 = 0;
  ***  *   **    ** * * * *   * **  *         ** *    * * ***     *** ** 

 **  *     *** **  * **  *****     ** *** of %.2fx^2 + %.2fx +%.2f = 0     * *  **  
** * * * ***     **     **  *  = (b*b-4*a*c);
**  **  *   **    * ******  (D < 0)
   **  *  *  *   ***** *
    *  * ** *  * *** **       * *** complex and *     ***** 
*****  *  * **     **** * * ******    = *  *  ** *  ** *    ***       ***
 *** *** ****   ***    **  ** *  * *  ** *** = * ****** ** ** *   *   * **
   **  * **  **     **  ****** 
**** ** **** *   * *   **** (D > 0)
*  * *  *  *    **    *
 **** **  ****** **** * **** *  *  real and * * **  **  
  *  *  *   *  **** * * * ** * ****    = ***   * **  *  + sqrt(D))/(2*a));
* *** *  ***  *      * *     **   *** = %.2f",(-b - sqrt(D))/(2*a));
** *    *  ** * *   **** ***
*  ***     **   ** *  **   *  (D == 0)
*    ** * *   ** * * *    
 **  ****  ********  ** *   ** **** real and same\n");
   **** *  * ** * **** * *****  **** * ** = x2 = %.2f",(-b + sqrt(D))/(2*a));
** *    ***  *** * ****  *   
}

Comments

Case 0: Wrong output
Case 1: Wrong output
Case 2: Wrong output
Case 3: Wrong output

---

your output lack of 1 space at line 8 when print out "Roots of ..."

Answer 7

Hidden content!
*** *   *     **    * *
* ** **  ********** **
int main()
{
   ** ******    * *** *  *  **** a,b,c,D = 0,x1 = 0,x2 = 0;
***** ****   * **  *       ** ****  *** *   *  *      ** *** *       **    * *

 ******* ** *  * *    ** **   **   * of %.2fx^2 + %.2fx +%.2f = 0  **    **  **
  *    *    **** *    **** **  = (b*b-4*a*c);
** *** ** ******  * ** ** (D < 0)
* * *  *   *  *** *** ** *   * 
* *** **  *  * ****  * *** ** *   **  ** complex and ****   * **  **
 *    ****** *  ****  ** * ***  = *****   **  * ** * ** *** *   *  ***
** ********** ***   *   *  ** * * **  =      *** * ***  * ****  ****
* * **  ** ****     *    
** **  *  * * ************** * (D > 0)
**** *****    *  * * * * 
  * * ** **  * *    ***  * ****   * *  **   ** real and ** ***** ** **  * 
  *   ** * * *  *  * ***** **  * * ** *  *  = ** * *    **  * * + sqrt(D))/(2*a));
 *  *    *    * *   * * *** * *     **   *   ***  = %.2f",(-b - sqrt(D))/(2*a));
* ** * * *** * *  *    * ** *** 
 ** ***  * ** *   * * *    *  (D == 0)
 *** ** ** **      * * *** 
 * **** ** * **  * *    * ***   real and same\n");
 *   **** *    ****    *   *  ***    * = x2 = %.2f",(-b + sqrt(D))/(2*a));
*** ** * ***  * * ** * **
}

Comments

Case 0: Wrong output
Case 1: Wrong output
Case 2: Wrong output
Case 3: Wrong output

Answer 8

Hidden content!
  ** ******** * ***
   ** * *** * *  *    *
int main()
{
****  ***  ****    *   * * * a,b,c,D = 0,x1 = 0,x2 = 0;
***** *  *** * ********   *  **  * *     * *** *****  * *** *****  * *   * * 

 *  **** *   ******  ****** *** ** **   * **   * of %.2fx^2 + %.2fx +%.2f = 0 *** **  *
 * *  *****  *** *  * *  ***  * = (b*b-4*a*c);
*   * * *   * * * * * *  ***  (D < 0)
 * ******** * ***** **  **  ***   
 * ***  *  * *  **  ****  ** *  **** * *  complex and **   *   **    *  *
 *** * ****  * **  *** **    *  *  * =    **  * ** *     **    *    ** *  
**  * **  *    *   * * **  *  * * ** * *  =     * * * *    * ***  *  **      ***
*   ***  *   * *    *** *
 *  *     **  * ** ****   *** (D > 0)
  * *  ** * ***   * *  ** **
  ******* ****  *  *    *  *      *  real and  *  *  *** *  * 
*     ** **  * * *  ******* ** * *    =  * ** * ** **  + sqrt(D))/(2*a));
 *   **  ** * ****   ***    ** ** * **   = %.2f",(-b - sqrt(D))/(2*a));
   * *****   * *  ***    * 
** * *** * *   * * ** * * * *  (D == 0)
        * *  ** **** **    * *  
* * ***     **    **  *  * *  *     * * ***  real and same\r\n");
 ***    *** *  *  *   * *   ** *     ** = x2 = %.2f",(-b + sqrt(D))/(2*a));
*** ***  ** * ****** *  * *    ** **
}

Comments

Case 0: Wrong output
Case 1: Wrong output
Case 2: Wrong output
Case 3: Wrong output

Answer 9

Hidden content!
 * *  ******* *       **
 *     ** *    * **
int main()
{
* * *  ****** ** *** * *    **    a,b,c,D = 0,x1 = 0,x2 = 0;
*  *  * * **  * *  *  *     * *   * * *   **  *    * ****  *   **  *  

*** ****    ** **  *    *** * ** *    * * of %.2fx^2 + %.2fx +%.2f = 0  *  * *  *  *  
***  ** *  ***** *   **  *  *  *** = (b*b-4*a*c);
 *  *  *     ***** ***   (D < 0)
  ** *     ********  *   
*  *** ***   ** *** * * * **  * * ** **  complex and ****    *** ** * 
  * *  *   ****    * *** ** * ***  **  * ** =  * ** * ** **  *   ****  * * 
*   **     **   ** * **  *    **   * =  *   * ** * ***  ***** **    *** ***
***  ****     *  ***  
***    *   ************** (D > 0)
 ********  ** ****  * * *  ***
* ***   *   ** ***** ***** *** ** real and  *  *    ** * ** *  
**   *  *    * * ****  *   * *** *****   ***** = ***  *     * ****  + sqrt(D))/(2*a));
* ***  * *    * **   ******  * ** *   = %.2f",(-b - sqrt(D))/(2*a));
**   ** *** *   *** **   
  ***  * **       *   * *  * (D == 0)
     *   *      * * ** *   ***
*   ****     *** *  *  *    **    * ***** real and same\r\n");
 **    ** *   *** **   **** *  **     * = x2 = %.2f",(-b + sqrt(D))/(2*a));
     *  ** * * **** *** * **   
}

Comments

Case 0: Wrong output
Case 1: Wrong output
Case 2: Wrong output
Case 3: Wrong output

Answer 10

Hidden content!
   *** **** * *** ***
**** * *  *  **  **
int main()
{
 * * * *  **** *****   *** * *****  *  a,b,c,D = 0,x1 = 0,x2 = 0;
**     **  ***** **   *** ***  ** ***   * ****** ****   **    **  * *   *

       **  * *** *   **  ** ***** *  ***  *****  of %.2fx^2 + %.2fx +%.2f = 0 are",a,b,c);
** *  *  * *        *  * = (b*b-4*a*c);
  **  * **** ***** * *** * * = (-b + sqrt(D))/(2*a);
** * *   *  **** *     * ** = (-b - sqrt(D))/(2*a);
   ** ***   **  ***      **** (D < 0)
 **   ** *    * *  **     *    
** ***** * * * * ***   *  **        **  complex and   *    *  ***  *** 
* **** ** ***** *  * *  ** * * * * ***   =    *     **   ***    **        *
*     ** **   ** ** *   * * **     * =  *  *** *   * ****  **   *    * 
* ** *   ****    **  *   **  **
 *** *******  ** **  * ****   * (D > 0)
*** * *  ********** **  **
**** ***  ***  ***  ** * *  *****  * **** * real and ** *  *   ***** 
** *  * * **   * ** *** *       * *  ***  = ****  * * **
      *** *  * **   **   *** **     ** = %.2f",x2);
* *   *****  ** *** ** *  ** ****
     **  *****   * * ***  (D == 0)
*  *  * **    ***   ** *     * *  ***
* * * * **   **   * ***** *** **  *   real and same\r\n");
**  **  *   **    ***   * * ***  * **    = x2 = %.2f",x1);
 *   **     ***    *  ** *
}

Comments

Case 0: Wrong output
Case 1: Wrong output
Case 2: Wrong output
Case 3: Wrong output