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

Hidden content!
#include *  ***** *** 
#include <math.h>
int main()
{
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}

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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****   *    *       * * * *

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

  *** ** * ****  ** *  * *  * *  *** * **    
  * * *   *  ****** ** *    ****   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)
*  *** *   *  * ** **   * *
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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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*  **  **         
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int main(){
** *  * * *   *  **  *     *   **  a,b,c;
 *  *** * ***  *     ** ** *  D;
* ** ****  *  *  **  **    * ***  %lf * **  ****   *  ***  * **   
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   **** *       *  *   * *  * ****   *** of %.2fx^2 + %.2fx + %.2f = 0  ** ** *  * 

** * * **        * * *** ***     * *   
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*  * ** * *** * * *  * * 
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   ** *  *** *  ** ** *   * ***  **   *  *    **  *   ******** * ** *  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()

{
    ***** *   *** *   * **   * *  ** *** * ** *     *    * 

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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)
**  * **  **  * *     **  *  
******     *  ***  *** **   * **  *   *******  * *  **   *   * of %.2fx^2 + %.2fx + %.2f = 0 are real and *  * ** *    * **** 
 ** * * **    * **     ******  ********    *    ** *    ** * ****  * ** = x2 = %.2f",x);
* **  * ****  * * ***  *    
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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