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

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

---

-----------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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***   **      * *****  *  * *    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

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#include   ** * * *  
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int main()
{
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  * * **  ** ********     *

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

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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

---

-----------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()

{
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*    *  ** * *  *    **   ** = (b*b-4*a*c);
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* * * * **      * ** *    ** *  = (-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);
   ***   * * ** * ** ***   * 
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  ***      **  * * ******** *** * * * ** ***** *  ** * **** ***** ** of %.2fx^2 + %.2fx + %.2f = 0 are real and  **** ** ***  ** 
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*    * * * * *** * *   **

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

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

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

** ** ** **  **** *  * *   *   *   
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**  ***  *   **** *** * 
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*   ** * * ** *     ***  * ****     **  *   *** ***       * * **** * real and same\n");
** *** *  ******* ***** * *     *  *   ***** *** * ** ****** **   **** ** * = x2 = %.2f",( (-b) / (2*a) ) );
***  **** ** ***  ** * *
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* * * *** ***** **    *** * * **     *     *   ***    *  **** *   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()

{
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* **  *****   **  * *   *** = (b*b-4*a*c);
*   ***   ******** * * * * *  = (-b + sqrt(D))/(2*a);
**     **  * * * ***   = (-b - sqrt(D))/(2*a);
  *    *  *  * * ** *    **** = -b/(2*a);
****  *   *** * * *       * *  =sqrt(-D)/(2*a);

***   **** * *  *  *     *** *** (D==0)
 **    ***     * *  **   **
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**   *  *    *       ** **   * 
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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