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