C++ Program to solve a linear equation using Bisection Method

Write and execute a C++ program to find the three roots of the equation x^3-4x-1=0.



PROGRAM

# include <iostream>
# include <math.h>
#include<iomanip>                    // for setw()
using namespace std;
float f(float);
const int maxit=15;
int main()
{
int count=0;
float a,b,x;
cout<<"\nEnter lower limit:";
cin>>a;
cout<<"\nEnter upper limit:";
cin>>b;
if(f(a)*f(b)>0)
cout<<"\nNo root is in the range.\n";
else
{
cout<<"\n\nLower limt"<<setw(20)<<"Upper limit"<<setw(20)<<"Function"<<setw(20)<<"Root";
while(count<=maxit)
{
x=(a+b)/2;
cout<<setw(20)<<a<<setw(20)<<b<<setw(20)<<f(x)<<setw(20)<<x;
if(f(x)*f(b)>0)
b=x;
else
a=x;
count++;
}
}
return 0;
}
float f(float x)                           
{
float n=(x*x*x)-(4*x)-1;            // the given function
return (n);
}