0 like 1 dislike
9.1k 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 | 9.1k 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 ** * ** * * *
#include ****** * * *****

int main()
{
* **** *** * * * * ** * a, b, c, determinant, 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 * ** * * > 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: Wrong output
Case 2: Wrong output
Case 3: Wrong output
0 like 0 dislike
Hidden content!
#include ** * **** *
#include * * * **** *

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


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


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

** ** * *** *** * ** condition for real and different roots
* ** ** ** ** ** * * (determinant > 0)
* * * * * **** * ** *
* ** ** * * * * * *** sqrt() function returns square root
* * * * ** * **** * * ** ** * * ** = * **** **** *
** * * * * * **** * *** * **** ** ** * = * ** ***** ** *

** ** * * *** ***** * * * * * ******* * ** * * ** *** ** of %.2fx^2 + %.2fx + %.2f = 0 are real and * * ** ** **
** *** **** ***** ** *** * ** *** * ** * **** **** = ** *** x1);
** *** * ** ** * * *** *** * ** * * ****** * * * * * * = *** ** * x2);
* * * *** ****

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

** ** **** ** ** * 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: Wrong output
Case 2: Wrong output
Case 3: Wrong output
0 like 0 dislike
Hidden content!
* * * * * **
*** * * ** ***** **
int main(void)
{
***** ** * **** * ** * * a,b,c,d;
* *** * ** ** * ** * * * ** * * *** %f *** * ** ******* * ** *
* * **** *** * * ** * ** *
* ****** ** * * ** **** **** *
*** * * * * * *** * * **** ** * ** ** * * * * of %.2fx^2 + %.2fx + %.2f = 0 are real and ***** * = %.2f\nx2 = * **** * + * * - * **
****** * * ** ** * * **
* * ********** * ** * (d==0){
**** *** *** *** * ** **** ** *** ******** * ** * * **** of %.2fx^2 + %.2fx + %.2f = 0 are real and same\nx1 = x2 = ** * **** ** + * ***
*** * ** * ** * **** *
** * ***** ** *** * (d<0) {
* ** *** * * ** * * **** ****** *** ** ** *** * of %.2fx^2 + %.2fx + %.2f = 0 are complex and * ** ** ** = * * * * = * *** *** **** * ** ** * ** * ** * * ** *
* * * ** ** **** * *
}
answered by (-204 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!
** * ** ** *** * * *
* ** ******
int main(void)
{
* * *** *** * ** a,b,c,d;
* * * *** * * * * * * * * %f ** ***** ****** * * *
** **** * ****** *** * ***
* ** *** * * * (d>0){
* *** *** *** * * **** ** * * ** **** *** ** * * * ** ***** of %.2fx^2 + %.2fx + %.2f = 0 are real and * * = %.2f\nx2 = ** ** * + * **** * - * ** **
* * * * * ***** * ** **
* * * * ** ** * * (d==0){
*** ** * ** * **** * *** ***** ** * * * ******* **** ***** of %.2fx^2 + %.2fx + %.2f = 0 are real and same\nx1 = x2 = * ** * + **** * **
*** * * *** * * *****
* ** * **** * ** * {
* **** ***** * * * * *** * * * * * *** * * *** ** of %.2fx^2 + %.2fx + %.2f = 0 are complex and * ** * * = ** * = *** * * ** * * ** ** ** ** * * * * *
**** * * * * *** ***
}
answered by (-204 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<math.h>
int main()
{
** ** * * ** * ** * a,b,c,d,x1,x2,x3,x4;
** * *** * ** ** **** * * %f * * * **** *** * * **
*** *** * ***** ****** * ** * * ****
* ***** * * * * * ***** *** * ** *
** ** * ** * ** ** ** * *** * * ** *
***** ******** * * ** * ** *
* * * ** * * ** * * ** ** * **
***** *** **** *** * **** * *** ** ** **
**** ** * * * ** **
* *** ** *** ** * * ** **** *** ** * * ** *** of %.2fx^2 + %.2fx + %.2f = 0 are real and * * * * ***** *** ** ** * * * **
* * *** *** * **
*** * ** * *** * * * * **** ** * * ** **
*** ** * ** * ******
** * * * *** * * * * * * ** * ** * * * ** * ** of %.2fx^2 + %.2fx + %.2f = 0 are real and same\nx1 = x2 = %.2f",a,b,c,x1);
*** ********* *** ** * ***
* * ** ** * ***** * * *** * ** ***
* * ** ** * * * * * * *
** * * **** ** * * *** ** **** *** ****** *** * ** *** ** of %.2fx^2 + %.2fx + %.2f = 0 are complex and different\nx1 = %.2f+%.2fi\nx2 = * * * * * *** **
** * * *** ** * * **
* * *** * * ******** ** 0;
}
answered by (-255 points)
0 0
prog.c: In function 'main':
prog.c:5:5: warning: implicit declaration of function 'scanf' [-Wimplicit-function-declaration]
     scanf("%f %f %f",&a,&b,&c);
     ^~~~~
prog.c:5:5: warning: incompatible implicit declaration of built-in function 'scanf'
prog.c:5:5: note: include '<stdio.h>' or provide a declaration of 'scanf'
prog.c:13:9: warning: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
         printf("Roots of %.2fx^2 + %.2fx + %.2f = 0 are real and different\nx1=%.2f\nx2=%.2f\n",a,b,c,x1,x2);
         ^~~~~~
prog.c:13:9: warning: incompatible implicit declaration of built-in function 'printf'
prog.c:13:9: 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 real and same\nx1 = x2 = %.2f",a,b,c,x1);
         ^~~~~~
prog.c:17:9: note: include '<stdio.h>' or provide a declaration of 'printf'
prog.c:21:9: warning: incompatible implicit declaration of built-in function 'printf'
         printf("Roots of %.2fx^2 + %.2fx + %.2f = 0 are complex and different\nx1 = %.2f+%.2fi\nx2 = %.2f-%.2fi",a,b,c,x3,x4,x3,x4);
         ^~~~~~
prog.c:21:9: note: include '<stdio.h>' or provide a declaration of 'printf'
0 like 0 dislike
Hidden content!
#include<stdio.h>
#include<math.h>
int main()
{
* ** * **** ** *** * **** a,b,c,d,x1,x2,x3,x4;
** * * *** ** ** ***** * %f *** * **** * * * * **
*** *** * * ** * * *** **
** *** * * ** * * ** ** ** ** *
**** ** * ** **** ** * ***
* ** ** ** * * * ** * ** *
*** **** * * ** **** ** * *** ** *****
* ** *** * *** * * ****** *** * ***
* * * * *
** ******** **** * *** **** * * ***** * * ** *** **** * * * of %.2fx^2 + %.2fx + %.2f = 0 are real and * * * ** *** * * * *** *
*** * * * * * *** * ** **
* ***** ** ** * ** * * * ** *** ** * * * **** **
* * * * ** * * *
** *** *** * * * ** * * ** * * ** * ******* ** ** ** * * of %.2fx^2 + %.2fx + %.2f = 0 are real and same\nx1 = x2 = %.2f",a,b,c,x1);
* *** ** * * * ** ***
*** ****** * ****** ** * * *** * *** *
* * * ** * ** * *** ** *
****** *** * * ** ** * * ***** * **** ***** **** of %.2fx^2 + %.2fx + %.2f = 0 are complex and different\nx1 = %.2f + %.2fi\nx2 = %.2f - * * * * *** ***
* * ** * ** * *
* * * ** ***** ** ** ** * **** 0;
}
answered by (-255 points)
0 0
Case 0: Correct output
Case 1: Wrong output
Case 2: Wrong output
Case 3: Wrong output
0 like 0 dislike
Hidden content!
#include<stdio.h>
***** * ** * ****
int main()
{
** * * * ** *** a,b,c,d,x1,x2,x3,x4;
* * ** * *** * ** * * ******* * %f * * *** * ****** * * ****
** ** * ****** * ***** * *
* *** ** * * * * * * *** * *****
* * * ** * * ******* * **** * *** * ** *****
* ** *** * * ** * ** * * *** *** ***
** **** **** * ***** * ****
* * ***** * ** * * * ** * * ** *** * * * *
*** **** ****** * * *
* * * ****** *** * ***** * **** * * * ** * ** ** ** * of %.2f x^2 + %.2f x + %.2f = 0 are real and *** * ** ** ** ** ** * **** **
** ***** *** ** * * *
* * ** *** * **** * ** *** * * ** *****
** * * * * ** ** * * *
*** *** ** * ** *** ** ** * ** **** ********* * * * ** of %.2f x^2 + %.2f x + %.2f = 0 are real and same\nx1 = x2 = %.2f",a,b,c,x1);
*** ********* * * * * *
****** *** * * ** * * *** * **** ***** ** * ****
* ** * * *** ***
****** * * * * * ** ** ** ** ** * * * * * ** ** of %.2f x^2 + %.2f x + %.2f = 0 are complex and different\nx1 = %.2f + %.2fi\nx2 = %.2f - **** ** * * * ** * ****
*** * * **** *** * *** ** ****
*** * * * ** ** *** * * 0;
}
answered by (-255 points)
0 0
Case 0: Wrong output
Case 1: Wrong output
Case 2: Wrong output
Case 3: Wrong output
0 like 0 dislike
Hidden content!
#include<stdio.h>
#include<math.h>
int main()
{
* **** ****** ***** * ** a,b,c,d,x1,x2,x3,x4;
* ** * * ** * ** * ** * * ** %f * * * * ** * * * * ** *
* *** ***** * * * * ** ** *
**** ** * ** ** * * * * * **** * ***
**** * ** * ****** * * ** * * * * *
** * ** * * ** ** ** * * * *
* *** **** * ** * * ** ** ** **
***** * * * *** * ***** ** ***** ***** * * *
* ** ** ** * * * ***
**** ** ** * ****** * * **** * *** * * ***** *** ** * ** * of %.2f x^2 + %.2f x + %.2f = 0 are real and *** * *** * **** ** *** ** *
* * * * * * ********
*** * * * * ** ** * * ** * ** * * **
*** *** * * * ** *
*** * * * ** ** *** *** * ** *** * * *** * of %.2f x^2 + %.2f x + %.2f = 0 are real and same\nx1 = x2 = %.2f",a,b,c,x1);
* * ** * *** * ** *
* ** * ** * * * ***** * *** ****** * *****
* * * ** **** **** **
**** ** ** * * ** * * * * ** ** *** * ***** ** of %.2f x^2 + %.2f x + %.2f = 0 are complex and different\nx1 = %.2f + %.2fi\nx2 = %.2f - * * * *** **
** * ** * * ** * ****
** ** * *** * * * * * *** * ****** **
* ** * * *** *** * **** 0;
}
answered by (-255 points)
0 0
prog.c: In function 'main':
prog.c:24:5: warning: implicit declaration of function 'system' [-Wimplicit-function-declaration]
     system("pause");
     ^~~~~~
0 like 0 dislike
Hidden content!
#include<stdio.h>
#include<math.h>
int main()
{
* * * **** ** * * **** * a,b,c,d,x1,x2,x3,x4;
*** ** * * * * * * * * %f * * ** * * * ***** *
** * *** * ** * * * * *
* * * * * * * *** * ** * **
* * ** **** * * * * *** **** ** **
** ******** ** * * *** * ** *
* * * ** **** *** *** * * * *
* **** ** * **** * * **** * ** * ** ** ** * ** **
** * * ***** * ** * **
**** *** *** * * * ** *** * * *** ** *** * * *** of %.2f x^2+%.2f x+%.2f=0 are real and different\n x1=%.2f\n * ** * **** * * * ** **
* * * * * * *** ***
**** *** * * ** * ***** * ** ******** *
* *** ** *** * **
*** ** ******** ** * ** * ** ** **** * * ** * * *** ** of %.2f x^2+%.2f x+%.2f=0 are real and same\n ****** ** ***
* ** *** *** ** **
* * * * ** * *** * *** * ** ** ** * * * *
****** ******* ** * ****
**** ** *** *** * * ** * * * * * * ** * *** ** of %.2f x^2+%.2f x+%.2f=0 are complex and different\n x1=%.2f+%.2f i\n x2=%.2f-%.2f ***** *** **** * * *
** ** * * ****
* ** * * * * * * * 0;
}
answered by (-255 points)
0 0
Case 0: Wrong output
Case 1: Wrong output
Case 2: Wrong output
Case 3: Wrong output
0 like 0 dislike
Hidden content!
#include<stdio.h>
#include<math.h>
int main()
{
*** * ** * * ** *** * a,b,c,d,x1,x2,x3,x4;
** *** * *** **** * %f * *** * * * *****
* **** ******* ** * **** ** **** ****
* *** *** *** * * * ** ** ** *******
* * * ** * ***** * *** * ** *** **
* * * * * * ** * * * *** **
** * * *** *** * * * * ** ** ** ****
* * * ** *** ** **** ** *** * ** * * * ** * **
**** * *** * * *
* * * ** ** ** * * * ***** * * * ***** *** **** of %.2f x^2+%.2f x+%.2f=0 are real and different\n x1=%.2f\n * *** * ***
*** *** * ** * ** ***** *
*** * ** ****** **** * ***** * * * ***** *
* * * * * *** * * ***
******* * * * ** * ** ** * ** ***** * *** ** ***** *** ** ** ** * of %.2f x^2+%.2f x+%.2f=0 are real and same\n * **** ** * *
* ** * * ** ** *** * ***
* ** * * * * *** * ** *** * ** * * **** ** * ***
* ******* * * ** * ***** *
** * * *** * **** * * ** * ** * * *** ** ***** of %.2f x^2+%.2f x+%.2f=0 are complex and different\n x1=%.2f+%.2f i\n x2=%.2f-%.2f ** ** ** ** * **
* *** ** * ** ***
* * * *** *** *** ** 0;
}
answered by (-255 points)
0 0
prog.c: In function 'main':
prog.c:18:16: warning: too many arguments for format [-Wformat-extra-args]
         printf("Roots of %.2f x^2+%.2f x+%.2f=0 are real and same\n x1=x2=%.2f",a,b,c,x1,x2);
                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Welcome to Peer-Interaction Programming Learning System (PIPLS) LTLab, National DongHwa University
English 中文 Tiếng Việt
IP:172.70.131.162
©2016-2025

No related questions found

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