#include <stdio.h>
#include <conio.h>
#include <stdlib.h>
#include <iostream.h>

int fn[20];
int n;
double a,b,x0;
double fnval;

float abso(float x)
{
	if (x<0) return -x;else return x;
}

double power(double a,int b)
{
	int i;
	double c=1;
	for (i=0;i<b;i++) c=c*a;
	return c;
}

void getfunction()
{
	int i;
	printf("Enter the degree of the function: ");
	cin >> n;
	printf("\nStart entering the coefficients\n\n");
	for (i=n;i>=0;i--)
	{
		printf("Enter coefiicient of degree %d: ",i);
		cin >> fn[i];
	}
}

void displayfunction()
{
	int i;
	printf("\nCurrent function is:\n ");
	for (i=n;i>-1;i--)
	{
		if (i==0) printf("%d",fn[i]);
		else printf("%dx^%d + ",fn[i],i);
	}
}

float getaccuracy()
{
	float no;
	printf("\nEnter the accuracy required: ");
	cin >> no;
	return no;
}

double fx(double x)
{
	int i;
	double ans=0;
	for (i=n;i>-1;i--)
	{
		ans=ans+fn[i]*power(x,i);
	}
	return ans;
}

void getinitialvals()
{
	float curr=0,prev=0;
	static float left=-100;
	for (int i=left;i<=100;i++)
	{
		curr=fx(i);
		a=i-1;b=i;
		if (curr==0)
		{
			left=i+1;
			printf("\nroot is %f",b);
			getinitialvals();
		}

		if (i==99)
		{
			printf("\n\nThe equation has no further real roots");
			exit(1);
		}

		if (curr*prev<0)
		{
			left=i;
			break;
		}
		prev=curr;
	}
}

void checkinivals()
{
	if(fx(a)>fx(b))
	{
		double temp=a;
		a=b;
		b=temp;
	}
}


int main()
{
	int i=0,itr=0;
	int j=1;
	clrscr();
	getfunction();
	float accu=getaccuracy();
	displayfunction();
	do
	{
		i=0;
		getinitialvals();
		checkinivals();
		cout << "\n\nInitial values are "<< a<< " and " << b << "\n";
		do
		{
			x0=(a+b)/2;
			fnval=fx(x0);
			printf("%d%15f%15f%15f%15f%15f\n",i+1,a,b,x0,fnval,b-a);
			if (fnval<0) a=x0; else b=x0;
			i++;
		} while (abso(b-a)>accu);

		printf("\n\nThe root of the equation is %f in %d iterations",x0,i);
		printf("\nPress any key to search for more roots");
		getch();

	} while(1);
}