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