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

int ask_int_input(void) {
  int a;
  int result;

  while (1) {
    printf("Enter a number: ");
    result = scanf("%d", &a);
    if (result == 1) {
      break;
    } else {
      printf("Input is not of type int. Try again\n");
      while (getchar() != '\n')
        ;
    };
  };

  return a;
}

int is_odd(int x) { return x % 2 == 0; }

int odd_or_even(void) {
  int i = ask_int_input();

  if (is_odd(i) == 1) {
    printf("Number is even");
  } else {
    printf("Number is odd");
  };

  return 0;
}

float ball_vol() {
  double pi = 3.1415;
  int a = ask_int_input();
  double r = sqrt(a / (4 * pi));
  double vol = 4 / 3 * pi * pow(r, 3);
  printf("The volume of the ball is: %f\n", vol);
  return vol;
}

int main(int argc, char **argv) {
  if (argc < 2) {
    printf("Please give at least one argument\n");
    return 1;
  };
  if (argc > 2) {
    printf("Too many arguments");
    return 1;
  };
  if (strcmp("help", argv[1]) == 0) {
    printf("help command \n");
    return 0;
  } else {
    ball_vol();
    odd_or_even();
  };

  return 0;
}