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