#include <stdio.h>
#include <math.h>
#include <unistd.h>

unsigned sleep(unsigned seconds);

double f(double x);
void gridsearch(double x0, double x1, double tol, int N);

// Driver program 
int main() 
{ 
    // Initial values
    double x0 =-3, x1 = 2; 
    gridsearch(x0, x1,1e-5,1000000); 
    return 0; 
} 


void gridsearch(double x0, double x1, double tol, int N) 
{ 
   int i;
   double x,dx,xhold;
    xhold=1e16;
    dx=(x1-x0)/N;
    for(i=0;i<N;i++){
    x=x0+dx*i;
    if (fabs(f(x))<=tol){
     xhold=x;
    }
    printf("%.15lf\t%.15lf\n",x,f(x));
    }
    printf("f(%.15lf) = %.15lf\n",xhold,f(xhold));
} 

// Define function

double f(double x) 
{ 
    double y;
sleep(1);
y=cos(x)-x;
    return y;
}