0 like 1 dislike
12.3k views

Write a program to find roots of a quadratic equation

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
[Exercise] Coding (C) - asked in Chapter 5: Selection Statements by (5.2k points)
ID: 28934 - Available when: 2017-10-26 18:00 - Due to: Unlimited

reopened by | 12.3k views
0 0
We will continue this question in few days
0 0
Everything is fixed. Enjoy your time with The Judge :)
0 0
ANNNNNNNNNNNNNNNNNNNNNNNNNNGRYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY
0 0
Your code has newline at the end sometime. You learned this lesson many times!
0 0
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.
0 0
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

56 Answers

0 like 0 dislike
Hidden content!
#include <stdio.h>
* ** * * * **
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 real and ** *** **
* ** * ** ** * * ** ** * * * * ** * *** ** * = %.2f\nx2 = %.2f",x1,x2);
** **** * *** *****

* * * ** * **** ** **** if(D==0)
** * * *** *** * *
**** ** *** ** ** * * * ** * ** ** ** * * **** of %.2fx^2 + %.2fx + %.2f = 0 are real and same\n",a,b,c);
** * * ** *** * ** ** *** * * ** ** *** ** ** = x2 = %.2f",x1);
*** *** ** * * *****
** * *** * * * ** *** *
* * * *** * * ** * *
** ** * *** ** * ** * * * *** **** * ***** * * of %.2fx^2 + %.2fx + %.2f = 0 are complex and ****** ********
* * ****** * * * *** * * ** * ** * *** * * ** *** * * * ** = * * *** ** *** *
**** ** **** * * * **** * ** ** * *** * * * * = * **** ** * * * * * ***** **
* ** * **** * ** *** *
** * *** *** * ** * ** 0;
}
answered by (-281 points)
0 0
Case 0: Correct output
Case 1: Correct output
Case 2: Correct output
Case 3: Correct output
0 like 0 dislike
Hidden content!
#include <stdio.h>
* *** * ******
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 %.2f x^2 + %.2f x + %.2f = 0 are real and * ** ** **
* ** * **** ** **** * * * **** * * ** * * * * ** * ** ****** = %.2f\nx2 = %.2f",x1,x2);
**** ** ** * *

* * * ** * * ** * if(D==0)
** * ** ********
* ***** * ****** *** *** * * **** * * * **** ** **** of %.2fx^2 + %.2fx + %.2f = 0 are real and same\n",a,b,c);
** * * ******** ** * * * * ** ** * ** * ** * * * = x2 = %.2f",x1);
** **** * *** ** ** * **
* * * * * ** * ** * *
** ** * * **** * **
** * ** ** ** ** ** * ***** * ***** * * * ** **** of %.2fx^2 + %.2fx + %.2f = 0 are complex and * ** * * * *
* * ** * ** ***** * ***** *** ** * ** * * ** * ** ** = ***** * * * ** *
*** * * **** * * * **** ****** *** * ** * ** * *** * * = * * * ** * * * * **
*** * *** * ** * ** ** **
* * *** *** ** * ** 0;
}
answered by (-281 points)
0 0
Case 0: Correct output
Case 1: Wrong output
Case 2: Correct output
Case 3: Wrong output
0 like 0 dislike
Hidden content!
#include <stdio.h>
#include <stdlib.h>

int main()

{
* * ** * * ** * *** a,b,c,x1,x2,D=0;
** ** **** ** * **
** * * ** * ** * * * ** ****** %f * *** *** * ** * * ** * *
** * *** *** * * ** *** *
** * ** **** * *** * ******* * **
* * * ** * ******* * + sqrt(D))/(2*a);
* *** * * * * ****** ** * * - sqrt(D))/(2*a);
* ** ** * * ** **
*** * *** * ***** * ** *
** * ***** * * **
** *** * ** * ****** * * * ** * ***** * **** *** ** * of %.2fx^2+%.2fx+%.2f=0 are complex and * ** * * *** * * * * ****
***** ** ***** * *
** **** *** *** *
****** ** * ** if(D==0)
*** * * *** * ******
**** * * * ** ******* * * ** * ** * * **** * of %.2fx^2+%.2fx+%.2f=0 are real and same\nx1=x2=%.2f",a,b,c,x1);
** * ** ** **** **** ******
* *** * ** ** * **** ****
*** * * *** ** ** * ** *** * ***
** ** * * *** * *
***** * * *** ***** * **** ***** ** * ****** * ** **** ** * ** of %.2fx^2+%.2fx+%.2f=0 are real and * * * * * * * * **** *
* ** * * * **** **
* * ***** * * * *****
*** ** * ** * **** * *
****** * * * ******* ** 0;
}
answered by (-127 points)
0 0
prog.c: In function 'main':
prog.c:12:14: warning: implicit declaration of function 'sqrt' [-Wimplicit-function-declaration]
     x1=(-b + sqrt(D))/(2*a);
              ^~~~
prog.c:12:14: warning: incompatible implicit declaration of built-in function 'sqrt'
prog.c:12:14: note: include '<math.h>' or provide a declaration of 'sqrt'
0 like 0 dislike
Hidden content!
* **** ****** *
int main()
{
* **** * * ** ** * * * * a,b,c,D;
* ** * * ** ** *** x1,x2,r,i;
* * ** ** * ** ** * **** * * * * **** *** * * ***** *
* * *** * *** *** * * ****** *
* ***** * **** *** *** ** ***
**** ** **** * ** *** * **** * ***** *
* *** **** * ***** * * **
* ** * ***** * **********
** * * * * * ** ** ** * * * ** * ** ** * ** * of %.2fx^2 + %.2fx + %.2f = 0 are real and same\n",a,b,c);
* * ******* * ** * * ** * ** * ** ***** * ** = x2 = %.2f",x1);
* * ****** * ** ** * ***
*** * * * * * if(D>0)
** ******* * * *** *** *
*** * * **** ** **** * ** ***** * *** ** * *** * * ** ** * of %.2fx^2 + %.2fx + %.2f = 0 are complex and * ** ** * * * ***
* ** **** ** **** **** *** * ** * * ** **** *** = %.2f\n",x1);
* ***** ** * * ** ** **** ** *** ** * * ** = %.2f",x2);
*** ** ******* * ***
** ** * * * * * * if(D<0)
** ** *** **** ** *** *
* * * *** ***** ** * * * * *** ** * *** ** **** * * *** of %.2fx^2 + %.2fx + %.2f = 0 are complex and different\n",a,b,c);
*** * * * ** * **** * * * * ** * * -b/(2*a);
* ** ** * ** ** ** ** **** * * ** * **** * **** ** * * *
* * * * * ** * * * * *** ** * ** * ************ * ** ** = %.2f+%.2fi\n",r,i);
* ** * * ** * * * *** * * * * **** *** * ** * = %.2f-%.2fi",r,i);
* * **** * ** ** * * * * *
}
answered by (-329 points)
0 0
prog.c: In function 'main':
prog.c:6:5: warning: implicit declaration of function 'scanf' [-Wimplicit-function-declaration]
     scanf("%f%f%f",&a,&b,&c);
     ^~~~~
prog.c:6:5: warning: incompatible implicit declaration of built-in function 'scanf'
prog.c:6:5: note: include '<stdio.h>' or provide a declaration of 'scanf'
prog.c:12:9: warning: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
         printf("Roots of %.2fx^2 + %.2fx + %.2f = 0 are real and same\n",a,b,c);
         ^~~~~~
prog.c:12:9: warning: incompatible implicit declaration of built-in function 'printf'
prog.c:12:9: note: include '<stdio.h>' or provide a declaration of 'printf'
prog.c:17:9: warning: incompatible implicit declaration of built-in function 'printf'
         printf("Roots of %.2fx^2 + %.2fx + %.2f = 0 are complex and different\n",a,b,c);
         ^~~~~~
prog.c:17:9: note: include '<stdio.h>' or provide a declaration of 'printf'
prog.c:23:9: warning: incompatible implicit declaration of built-in function 'printf'
         printf("Roots of %.2fx^2 + %.2fx + %.2f = 0 are complex and different\n",a,b,c);
         ^~~~~~
prog.c:23:9: note: include '<stdio.h>' or provide a declaration of 'printf'
0 like 0 dislike
Hidden content!
*** * ** * *
int main()
{
**** ****** ** *** *** * ** a,b,c,D;
** ** ** *** **** ** * * x1,x2,r,i;
* **** * * * *** ***** *** * ** ***** * *** *** ** **** * *
** * ** * * * * *
* ** * ** * * * ** * *
* ** * * * *** ** * ** ** **
*** * ****** **
* ** ***** ** ***** *
* **** * * ** ** ** * * *** ** ** ** * * ** **** * * of %.2fx^2 + %.2fx + %.2f = 0 are real and same\n",a,b,c);
**** * * * * ** * ** ** * * * * ** ** * * = x2 = %.2f",x1);
* ** * * * * * * ****** *
* ***** ** * ** * ***** * ** if(D>0)
* * * *** *** * ***** **
** * * * * * **** * * ** ** * **** * * ** ** * *** of %.2fx^2 + %.2fx + %.2f = 0 are complex and *** * ** * **
****** *** **** * * * * ** **** **** * * **** * * = %.2f\n",x1);
* **** ** *** *** **** ** * ** * * * *** ** **** * = %.2f",x2);
** ** * *** * * *****
* ** * * ** * * *** * ** * if(D<0)
** ** * ** * *
**** ** * * * ** *** ** ** * ** * **** * of %.2fx^2 + %.2fx + %.2f = 0 are complex and different\n",a,b,c);
*** ** *** ** * *** ** *** *** * * * ** *** -b/(2*a);
* ** *** ** **** **** ** * * * **** **** ** *** *** **
* * *** ****** * * * * ** ** * * * *** * * * * * = %.2f+%.2fi\n",r,i);
** ** * * ** ** ** ******** * * * * * * * ** = %.2f-%.2fi",r,i);
** **** * *** **** * *
}
answered by (-329 points)
0 0
prog.c: In function 'main':
prog.c:8:12: warning: implicit declaration of function 'sqrt' [-Wimplicit-function-declaration]
     x1=(-b+sqrt(D))/(2*a);
            ^~~~
prog.c:8:12: warning: incompatible implicit declaration of built-in function 'sqrt'
prog.c:8:12: note: include '<math.h>' or provide a declaration of 'sqrt'
0 like 0 dislike
Hidden content!
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
int main()
{
**** * ** * * * **** a,b,c,d,x1,x2;
* ** ** ** * *** **** * ** ** ******** ******* *** * *
* * * ** ** **** * * * * * *
*** * ** * * ** ** **
* *** * * **** * ** * * *** **** * ** **
* * * *** **** *** * **** * *
* ****** * ** *** * *
* *** ** * * **** ** *** * ** * ** * ** ** * *** *** of %.2fx^2 + %.2fx + %.2f = 0 are real and *** * ***** *** * *
* * *** *** ** * * * ***** ** ** ** * **** * ** = %.2f\n",x1);
* * * * ** * ***** * ** * * * * * * * * * ********* = %.2f",x2);
** * * ** ******** * ** *
*** * ** * ** * *** * * * if(d==0)
* *** **** * * * *
** * ** * *** ** * **** ** * ***** *** * * of %.2fx^2 + %.2fx + %.2f = 0 are real and same\n",a,b,c);
* * ** * ***** *** * ** *** ***** * **** * * * * **** = x2 = %.2f",x1);
* **** *** *******
* **** * **** * *
* * ** * * ** * ***
* * * * *** ** * * * * *** **** * ** ***** ** ** ** of %.2fx^2 + %.2fx + %.2f = 0 are complex and * * * *** * *
* * * * ** * ** * * *** ******* *** * **** * = ****** ** **** * * *
**** * * * ** **** ***** ** ** * * ***** * * ** ** *** * ** = * * ***** *** * ** **
**** * *** * *** * ***
** ** * ** * ** * * 0;
}
answered by (-498 points)
0 0
Case 0: Correct output
Case 1: Correct output
Case 2: Correct output
Case 3: Correct output
0 like 0 dislike
Hidden content!
#include <stdio.h>
#include <stdlib.h>
#include <math.h>

int main()
{
* ** * * ***** * ** **** **** * a,b,c,d,x1,x2;
* ** **** *** ** * * *** * * ** ** * ** * ** *** **
** *** * ** ** *** * * * ** ***
** * * * * ** ** *** * = (-b + sqrt(d))/(2*a);
* * * ** * *** * * ** = (-b - sqrt(d))/(2*a);
** ****** ** * * * * **
* **** ** ** ** * * * ***** *** **** * **** * **** **** of %.2fx^2 + %.2fx + %.2f = 0 are real and different\n",a,b,c);
* ** ** *** * * **** **** * * ** *** **** *** *** ** * * * ****** * * * ****** ** * ******* *** ***** ** ***** ** * * * * ***** * ** ** * * ** *** ** **** ** * **** * * * = %.2f\n",x1);
* * ** * **** ** *** * **** *** ** * * **** ** * *** * ** * * ** * * * * * * ** *** * *** *** * ** * ** * * * **** ** * * ** * ** * *** ***** **** * * * **** *** * * ** = %.2f",x2);}
** ** * * * * * if(d==0)
* *** * ** ** ** * ** *** * * *
***** * * * * * *** * * * * * **** ** * ** * *** ***** * * * * of %.2fx^2 + %.2fx + %.2f = 0 are real and same\n",a,b,c);
* ******** ***** * ** ** * * ** * * * * * *** ** * * *** * * * *** * * * ** ** * * ** ** ****** ** * = x2 = %.2f",x1);}
* * * * * * ****** ***
** ***** * * * * * * * ** *** * * * *** ** ** **** ** * * *** of %.2fx^2 + %.2fx + %.2f = 0 are complex and different\n",a,b,c);
** ** * *** *** *** * * *** **** ** * * *** **** ** = ***** **** **** *
* ** ** * ** ** * ** * * * * ** ** * *** * * **** = ** * * * *** * * *
* * ** * * * * **** *** * 0;
}
answered by (-108 points)
0 0
Case 0: Correct output
Case 1: Correct output
Case 2: Correct output
Case 3: Correct output
0 like 0 dislike
Hidden content!
#include * ** * * *
#include ** * *** ***

int main()

{
*** **** ** ** * **** ** * ** **** * *
**** * ** * ***** ** * * * * * %f **** * * ** * * * * * ****

* *** * * * * * * * * ***** * *
** * * *** * * * * * + sqrt(D))/(2*a);
* *** * * ** * * ** ** * * - ** *
* *** ** ** * **** *
** * * ** *** *** ** *** *

* *** * * * ** *** *** (D==0)
* *** * ******* ****
** ** * * ** * * ** ** ** * * * * * ** **** *** ** * of %.2fx^2 + %.2fx + %.2f = 0 are real and same\nx1 = x2 = * * * * * * *
** *** **** ** * * *
** * ** * *** ** * ** * if (D>0)
**** * * ** ** *** ** * *
* * *** * ** ** ** * *** *** ***** ** * * * * * * of %.2fx^2 + %.2fx + %.2f = 0 are real and different\nx1 = %.2f\nx2 = ****** * **
*** * * * * * **** * ***
* ** ** * * ** * ** ** **
** * *** *** **
* * ** * ** * * * ** ** ** ** **** *** of %.2fx^2 + %.2fx + %.2f = 0 are complex and different\nx1 = %.2f+%.2fi\nx2 = * * ***** * *** *
*** ** * *** * * * *

* *** * * *** ***** 0;

}
answered by (-249 points)
0 0
Case 0: Correct output
Case 1: Correct output
Case 2: Correct output
Case 3: Correct output
0 like 0 dislike
Hidden content!
#include * * ** * ****
#include ** * * ** ** ***
int main(void)
{
float a,b,c, D, x1, x2,i;
*** * **** **** * * ** * *** * ** %f * ** * &a, &b, &c);
* * ** * *** ** * * **
* * ** * ** * ** **** (D>0)
** ** ** * ** *
* * ** ** ** *** **** * * * ** * * ** ***** * * * * ****
** ** ** ** * ***** * *** * * * * * ** ** * ***** **

* * * ** *** * * ** ** * * ** **** * *** ** * ***** * * of %.2fx^2 + %.2fx + %.2f = 0 are real and *** * = %.2f\nx2 = *** * * * *
* ** *** ****** ** *
** * ** **** *** * * *** if (D==0)
* *** * * ***** * * * *
** * * * ** * * * * * ** * * * * ** *** * **
**** ** **** * * ** * ** * ** * ** ***** * **** *** of %.2fx^2 + %.2fx + %.2f = 0 are real and same\nx1 = x2 = * *** *** *** ****
**** *** **** * *
*** * * ** *** ** ** *
* ** * * * * * *** **
* ** ** ** *** * ** * *   x1=x2 = -b/(2*a);
* **** ** * * * * *** ** **** * * ** * * *
** * * * * * * ** * * *** * **** *** ** *** ** * * of %.2fx^2 + %.2fx + %.2f = 0 are complex and * ** * = ***** ** = **** * ** ** ** x2,i);
*** * * **** ***** **



* **** * * *** ** * * 0;
}
answered by (-304 points)
edited by
0 0
prog.c: In function 'main':
prog.c:10:16: warning: implicit declaration of function 'sqrt' [-Wimplicit-function-declaration]
         x1=(-b+sqrt(D))/(2*a);
                ^~~~
prog.c:10:16: warning: incompatible implicit declaration of built-in function 'sqrt'
prog.c:10:16: note: include '<math.h>' or provide a declaration of 'sqrt'
0 0
Case 0: Correct output
Case 1: Wrong output
Case 2: Wrong output
Case 3: Wrong output
0 0
Case 0: Correct output
Case 1: Correct output
Case 2: Wrong output
Case 3: Correct output
0 0
Case 0: Correct output
Case 1: Correct output
Case 2: Wrong output
Case 3: Correct output
0 0
prog.c: In function 'main':
prog.c:21:5: error: expected ';' before '{' token
     {
     ^
0 0
Case 0: Correct output
Case 1: Correct output
Case 2: Wrong output
Case 3: Correct output
0 0
Case 0: Correct output
Case 1: Correct output
Case 2: Wrong output
Case 3: Correct output
0 0
Case 0: Correct output
Case 1: Correct output
Case 2: Correct output
Case 3: Correct output
0 like 0 dislike
Hidden content!
#include * ** * ** * * *
#include *** ** * **

int main()
{
* * * * * * * a, b, c, *** * x1,x2, realPart, * * ** *


* ****** * ***** * * * ** **** ** %lf * *** *** *** ** &b, &c);


*** * ** * * ** ** * **** * * = b*b-4*a*c;

* * ** *** * * ** condition for real and different roots


***** * * * ** * **** * ** for real and equal roots
* *** * * * *** ****** ** * * * (determinant == 0)
**** ******** * * ** *
**** * ***** **** * * ** *** * ** * ** * * = x2 = -b/(2*a);
* ** ** ** ** * ** * * * *** ** * *** ** ***** * of %.2fx^2 + %.2fx + %.2f = 0 are real and **** * ** ** a,b,c);
****** ** * * * * *** ** * * *** **** *** * * * * = x2 = * * x1);
* *** * *** * ** **** *****

***** * *** * * ** ** if (determinant > 0)
*** ** ** **** ** * * * **
** *** * * * * * sqrt() function returns square root
** ** **** ***** ***** * *** *** *** ** = ***** * * **
** ** * ** **** ** * **** * * * * * = * ** * * * * * **

* * ** ** * *** * ** * ** * * * * * ******* ** *** *** of %.2fx^2 + %.2fx + %.2f = 0 are real and * * ** * **
** * *** ** ** *** ** * * * ** * * * * * ** * * ** * = **** *** * x1);
* *** *** * * ** * ** * ** * ** * * * ** ** * *** ** * = * ** * * x2);
** ***** * ** *** * * *** * if roots are not real
* * * * *** ** ** * *
* * ** * *** * *******
** **** * * * *** *** ****** *** ** ***** ****** = -b/(2*a);
** * ** * *** ** * ** ** * *** ** * ** *** * = ** **** *
* * * *** * ** * ** * ** **** * **** ** ** *** * ** * * *** of %.2fx^2 + %.2fx + %.2f = 0 are complex and *** *** a,b,c);
* *** * *** * * ** * ** * ** * * * * *** * ** = * * ** ***** realPart, * * **** *
** * **** ** **** * ****** **** * * *** = *** * * realPart, *** *** *
*** * * * * * * * * *

**** *** *** * * * * * 0;
}
answered by (-167 points)
0 0
Case 0: Correct output
Case 1: Correct output
Case 2: Correct output
Case 3: Correct output
Welcome to Peer-Interaction Programming Learning System (PIPLS) LTLab, National DongHwa University
English 中文 Tiếng Việt
IP:172.69.17.67
©2016-2025

No related questions found

12,783 questions
183,442 answers
172,219 comments
4,824 users