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