False Position Method or Regula Falsi Method - C Program

#include<stdio.h>

#include<conio.h>

#include<math.h>

float f(float x)

{

return (x*x*x-5*x+1);

}

int main()

{

clrscr();

int itr=0, maxitr;

float x1,x2,x3,x4,aerr;

printf("\nProgram to find Root of an Equation by Regula falsi Method\n\n");

printf("\nEnter value of x0, x1, allowed error and maximum iteration\n");

scanf("%f %f %f %d", &x1, &x2, &aerr, &maxitr);

x3=((x1*f(x2))-(x2*f(x1)))/(f(x2)-f(x1));

printf("\n\nIn iteration %d, Value of x3 =\t%f",itr+1,x3);

do

{

if (f(x1)*f(x3)<0)

x2=x3;

else

x1=x3;

x4=x3;

x3=((x1*f(x2))-(x2*f(x1)))/(f(x2)-f(x1));

itr++;

printf("\nIn iteration %d Value of x=\t%f", itr+1,x3);

if (fabs(x4-x3)<aerr)

{

printf("\n\nAfter %d iteration, Root= %f", itr,x4);

getch();

return 0;

}

}

while (itr<maxitr);

printf("\n\nSolution does not converge Iteration not sufficient");

getch();

return 1;

}