0 like 1 dislike
11.9k 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 | 11.9k 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:172.69.130.53
©2016-2025

No related questions found

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