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

Show more...

Comments

We will continue this question in few days

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Everything is fixed. Enjoy your time with The Judge :)

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ANNNNNNNNNNNNNNNNNNNNNNNNNNGRYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY

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Your code has newline at the end sometime. You learned this lesson many times!

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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.

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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!
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# * ** * ***  * *    * * 
int main()
{

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********  *** * * * *      *  * * ** ** ***   * *    **   *** ** * ** = -%.2f+%.2fi\n", realPart,imaginaryPart);
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 *  *  * *  **  ***  *
   ****   ***    ** *** ***  *    0;

}

Comments

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

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/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

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

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

Answer 2

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#include *    *  **  *
#include <math.h>
int main()
{
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*    ******    * **    
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  ** **  *   **      ** *  * *    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

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-----------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()
{
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 * *** *  **  **  ***    *  **  *  *      * * * *** ***     * *  * of %.2lfx^2 + %.2lfx + %.2lf = 0 are real and same\nx1 = x2 =  * **  ** * * a, b, c, root1);
  * * **  *   * *  * **

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 ****        ****  * **   *
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   *    *****   *  ****** ******  *  ** **** *   ***   ** = * * *  *

*  *   ** *** *   ***  ****    **     ** ** ** * * * *  *     ** *  ****  *   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

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-----------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

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-----------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)
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*****   *  **** * * **      ***    *    **    *  ****  * ****** = %.2f",xx);
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  *****   ** * *  * **  ** *     ***** *  **  *****   **** **** 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

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

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/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!
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*  * ** *  *  * * **
int main(){
   ** *** **  *****   * ****** a,b,c;
 ** * **** **  **  *  * * * ** *   D;
  *   *  **  **   * ** * * ** *   * *  ** %lf *  **    * * ** * * * *  ***   *   
* ** **  *   *  **   * * **** *** **  - 4*a*c ;

 **  ** * **   * ** * ** ** *  * ** * **     of %.2fx^2 + %.2fx + %.2f = 0   ** *   

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 * **  * * **           ** *     *     ****  ** * ** ** * ** ***** = ***  ****  **  (-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   * ** **   
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 **   ***   ** **  ** *** 
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* ** *    **  **   *   * ** *
 * ** *  *    *  **      *** ****  *  *   ** * **  *   *   * *    * of %.2fx^2 + %.2fx + %.2f = 0 are complex and * ***  **  * * *** *  
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***  * ***  * ** ****** ****    *** **  * *   *     *   *      ** =  * **    *  *  ** **    *  * 
 *   ******   *** *     * *

    ** **  ***   ** * * *  *     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