Bisection method c program

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

double F(double x)
{
    //This return the value of the function
    return (pow(x, 3) + 3 * x - 5);
}

int main()
{
    printf("This program illustrates the bisection method in C\n");
    printf("x^3 + 3*x - 5 = 0\n");

    double x0, x1;

    printf("Enter the first approximation to the root : ");
    scanf("%lf", &x0);
    printf("Enter the second approximation to the root : ");
    scanf("%lf", &x1);

    int iter;

    printf("Enter the number of iterations you want to perform : ");
    scanf("%d", &iter);

    int ctr = 1;
    double l1 = x0;
    double l2 = x1;
    double r, f1, f2, f3;

    //We check if the initial approximations are the root or not
    if (F(l1) == 0)
        r = l1;
    else if (F(l2) == 0)
        r = l2;
    else
    {
        while (ctr <= iter)
        {
            //this is an implementation of the algorithm mentioned above
            f1 = F(l1);
            r = (l1 + l2) / 2.0;
            f2 = F(r);
            f3 = F(l2);
            if (f2 == 0)
            {
                r = f2;
                break;
            }
            printf("The root after %d iteration is %lf\n", ctr, r);
            if (f1 * f2 < 0)
                l2 = r;
            else if (f2 * f3 < 0)
                l1 = r;
            ctr++;
        }
    }

    printf("\nThe approximation to the root is %lf", r);
   
    return 0;
}

Output : 

This program illustrates the bisection method in C
x^3 + 3*x - 5 = 0
Enter the first approximation to the root : 1
Enter the second approximation to the root : 2
Enter the number of iterations you want to perform : 9
The root after 1 iteration is 1.500000
The root after 2 iteration is 1.250000
The root after 3 iteration is 1.125000
The root after 4 iteration is 1.187500
The root after 5 iteration is 1.156250
The root after 6 iteration is 1.140625
The root after 7 iteration is 1.148438
The root after 8 iteration is 1.152344
The root after 9 iteration is 1.154297

The approximation to the root is 1.154297