quadratic equation

[img]http://img19.imageshack.us/img19/9384/f5.JPG[/img]

#include <stdio.h>
#include <math.h>
void main()
{
double a,b,c,disc,x1,x2;
printf("To find the roots of a quadriatic equation with real roots\n")
disc=b*b-4*a*c
if(disc<0)
printf("The roots are complex",disc);
if(disc>=0)
printf("-b+sqrt(disc)/2a",x1);
printf("-b-sqrt(disc)/2a",x2);

This is what i wrote, i know it is missing alot
but I really dunno how to do it, so can anyone help me to do the rest
so it can run well

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14 Years

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14 Years Ago

Last Post by Killer_Typo

Hello,

To start with, when you declare variables, initialize them right away:

double a = b = c = disc = x1 = x2 = 0.0;

Next, you will need to use cin or scanf to read the data into variables.

You will also need to check your operator precidence. Example:

4 * 3 / 4 + 6 = 9

4 * 3 / (4 + 6) = 4 * 3 / 10 = 1.2

Your disc equation will need help.

Let us know how it works.

Christian

double a = b = c = disc = x1 = x2 = 0.0;

It uses equal? i dun get it?

scanf all variables?

Hello,

double a = b = c = disc = x1 = x2 = 0.0;

declares all of those variables as double values, and then assigns them a value of zero.

Remember that in C, = is the assign operator, and == is the equals operator.

scanf(%d, variable); scans in an integer
scanf(%lf, variable); scans in a floating double number

You are going to need to read your C or C++ book to find out how to set these things up properly, and gain a greater understanding of what you are trying to do.

Give it a shot.

Christian

Please dont post such huge pics,my connection is slow at the best and it take a long time to download huge pic :-(

Hello , this was my homework in the past
i hope it will help you

Attachments

polynomial.cpp (3.19 KB)

//   
//  12288
//  : 424103019
//Question 2
//Polynomial.cpp
enum Error_code {success,fail};
class Polynomial {
public:
	Polynomial(int = 10);
	Polynomial(const Polynomial &);
	Polynomial operator+(const Polynomial &);
	Polynomial operator-(const Polynomial &);
	Polynomial operator*(const Polynomial &);
	Polynomial &operator=(const Polynomial &);
	Polynomial &operator+=(const Polynomial &);
	Polynomial &operator-=(const Polynomial &);
	Polynomial &set(int=0,double=0);
	void print()const;
	double Get(int =0);
	~Polynomial();
private :
	double *a;
	int grade;
};
#include <iostream>
using std::cout;
using std::cin;
using std::endl;

Polynomial::Polynomial(int s)
{
	grade = (s>0 && s<1000 ? s : 10);
	a = new double[grade+1];
	for(int i=0;i<=grade;i++) 
		a[i] = 0;
		
	
}
Polynomial::Polynomial(const Polynomial &x)
{
	grade = x.grade;
	a = new double [grade+1];
	for(int i=0;i<=grade;i++)
		a[i] = x.a[i];

}
Polynomial &Polynomial::operator =(const Polynomial &x)
{
	if (this != &x)
	{
		if (grade != x.grade) {
			grade = x.grade;
			delete a;
			a = new double [grade+1];
		}
		for(int i=0;i<=grade;i++) 
			a[i] = x.a[i];
		
		
	}
		return *this;
}
			
Polynomial Polynomial::operator +(const Polynomial &x)
{
	int s = grade >= x.grade ? grade : x.grade;
	Polynomial temp(s);
	
	for(int i=0;i<=x.grade;i++)
		temp.a[i] += x.a[i];
	for(int j=0;j<=grade;j++)
		temp.a[j] += a[j];
	return temp;
}
Polynomial Polynomial::operator-(const Polynomial &x)
{
	int i=0,j;
	int s = grade >= x.grade ? grade : x.grade;
	if ((x.grade == grade) && (a[grade]-x.a[x.grade]==0) ) {s--;i = 1;}
	Polynomial temp(s);
	for(j=i;j<=grade;j++)
		temp.a[j-i] += a[j];
	for(j=i;j<=x.grade;j++)
		temp.a[j-i] -= x.a[j];
	return temp;
}
Polynomial &Polynomial::operator +=(const Polynomial &x)
{
	*this = *this +x;
	return *this;
}
Polynomial &Polynomial::operator -=(const Polynomial &x)
{
	*this = *this - x;
	return *this;
}
Polynomial &Polynomial::set(int exp,double coff)
{
	if (exp >=0 && exp<=grade) {
		a[exp] = coff;
		
	}
	return *this;
}
Polynomial Polynomial::operator*(const Polynomial &x)
{
	int s = grade + x.grade,i,j;
	Polynomial temp(s);
	for(i=0;i<=grade;i++)
		for(j=0;j<=x.grade;j++) 
			temp.a[i+j]+=(a[i]*x.a[j]);
	
	return temp;
}

void Polynomial::print()const {
	for(int i=grade;i>=0;i--) 
		cout << (i!= grade && a[i]>=0 ? '+' : ' ' )
		<< a[i] <<  "x^" << i;

	cout << endl;
}
double Polynomial::Get(int exp)
{
	if (exp >= 0 && exp<=grade)
		return a[exp];
		return 0;
}
Polynomial::~Polynomial()
{
	delete []a;
}
int main()
{
	Polynomial A(2),B(5),C;
	
	A.set(2,4).set(1,-5).set(0,6);
	
	B.set(5,1).set(4,4).set(3,3).set(2,-2).set(0,16);
	cout << "A = ";
	A.print();
	cout << "B = ";
	B.print();
	C = A+B;
	cout << "C = A+B : ";
	C.print();
	C = A-B;
	cout << "C = A-B : ";
	C.print();
	C = B-A;
	cout << "C = B-A : ";
	C.print();
	C = B*A;
	cout << "C = A*B : ";
	C.print();
	C += B;
	cout << "C += B : ";
	C.print();
	C -=A;
	cout << "C -= A : ";
	C.print();
	cout << "The coffecient of exp 0 in B is :" << B.Get(0) << endl;
	return 0;
}

Please dont post such huge pics,my connection is slow at the best and it take a long time to download huge pic :-(

sorry about that

Hello , this was my homework in the past
i hope it will help you

urs is too hard for me

This is my project thats due tomorrow
can someone do the rest for me?
i am lack of time now....
coz i got my final tomorrow too

This is my project thats due tomorrow
can someone do the rest for me?
i am lack of time now....
coz i got my final tomorrow too

they dont do others homework here, your going to have to do it, best that you can hope for is a direction to go in, and maybe some hints, but you cant expect someone to just write all the code for you.