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  *** * *   *   ***** *  **  ****  *
 * *   ** * ***  *  * **  *  = (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;

}

Comments

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

---

/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

---

-----------Re-judge-----------
Case 0: Wrong output
Case 1: Wrong output
Case 2: Wrong output
Case 3: Wrong output

---

-----------Re-judge-----------
Case 0: Correct output
Case 1: Correct output
Case 2: Wrong output
Case 3: Correct output

Answer 2

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;
}

Comments

/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

---

-----------Re-judge-----------
Case 0: Wrong output
Case 1: Wrong output
Case 2: Wrong output
Case 3: Wrong output

Answer 3

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;
}

Comments

/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

---

-----------Re-judge-----------
Case 0: Wrong output
Case 1: Wrong output
Case 2: Wrong output
Case 3: Wrong output

---

/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

---

-----------Re-judge-----------
Case 0: Wrong output
Case 1: Wrong output
Case 2: Wrong output
Case 3: Wrong output

---

-----------Re-judge-----------
Case 0: Correct output
Case 1: Correct output
Case 2: Correct output
Case 3: Correct output

Answer 4

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;

}

Comments

/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

---

-----------Re-judge-----------
Case 0: Wrong output
Case 1: Wrong output
Case 2: Wrong output
Case 3: Wrong output

---

/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

---

-----------Re-judge-----------
Case 0: Wrong output
Case 1: Wrong output
Case 2: Wrong output
Case 3: Wrong output

---

-----------Re-judge-----------
Case 0: Correct output
Case 1: Correct output
Case 2: Correct output
Case 3: Correct output

Answer 5

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;
}

Comments

/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

---

-----------Re-judge-----------
Case 0: Wrong output
Case 1: Wrong output
Case 2: Wrong output
Case 3: Wrong output

Answer 6

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;

}

Comments

/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