Finding root of this equation e^-x+cos(x^3+2*x-1) -12 using iteration method it's -2. 5486 exactly but it's oscillating

Question

Help me correct this code so that it will be able to find root of any trancedental equation using iteration method.

Here's my code
Thanks in advance

#include<stdio.h>
#include<conio.h>
#include<math.h>
#define e1 2.7182818

#define f(x) pow(e1,-x)+cos(pow(x,3)+2*x-1)-12
#define g(x) -log(12-cos(pow(x,3)+2*x-1))

int main()
{
int step=1, N;
float x0, x1, e;

/* Inputs */
printf("Enter initial guess: ");
scanf("%f", &x0);
printf("Enter tolerable error: ");
scanf("%f", &e);
printf("Enter maximum iteration: ");
scanf("%d", &N);
/* Implementing Fixed Point Iteration */
printf("\nStep\tx0\t\tf(x0)\t\tx1\t\tf(x1)\n");
do
{
x1 = g(x0);
printf("%d\t%f\t%f\t%f\t%f\n",step, x0, f(x0), x1, f(x1));

step = step + 1;

if(step>N)
{
printf("Not Convergent.");
break;
}

x0 = x1;

}while( fabs(f(x1)) > e);

printf("\nRoot is %f", x1);

getch();
return(0);
}

Answer 1

Do not use #define. It's too dangerous.

#define SQUARE(a) a*a

int main()
{
int f = SQUARE(3 + 3); // 3 + 3*3 + 3 = 15, not 16
return 0;
}

If you want to use #define, put breakets around every variable. In my example
#define SQUARE(a) (a)*(a)