0 like 1 dislike
12.1k 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 | 12.1k 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:172.70.178.44
©2016-2025

No related questions found

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