#include <stdio.h>
#include <stdlib.h>

int main(int argc, char** argv) {

  // decode the command line arguments
  //
  long ival = atoi(argv[1]);
  float fval = atof(argv[1]);

  /*
  // if else if example
  //
  if (ival < (long)0) {
    fprintf(stdout, "%f is a negative number\n", fval);
  }
  else if ((fval >= (float)0.0) && (fval <= (float)1.0)) {
    fprintf(stdout, "%f is in the range [0,1]\n", fval);
  }
  else if (fval > 1.0) {
    fprintf(stdout, "%f is greater than 1.0\n", fval);
  }
  else {
    fprintf(stdout, "**> I don't know what it is (%f)\n", fval);    
    return -1;
  }
  */
  
  // switch statement
  //
  fprintf(stdout, "using switch:\n");

  char grade = argv[1][0];

  switch(grade) {
  case 'A':
    fprintf(stdout, "%c: Excellent!\n", grade);
    break;
  case 'B':
  case 'C':
    fprintf(stdout, "%c: Well done\n", grade);
    break;
  case 'D':
    fprintf(stdout, "%c: You passed\n", grade);
    break;
  case 'F':
    fprintf(stdout, "%c: Better try again\n", grade);
    break;
  default:
    fprintf(stdout, "%c: Invalid grade\n", grade);
  }

  fprintf(stdout, "using if/else if:\n");
  if (grade == 'A') {
    fprintf(stdout, "%c: Excellent!\n", grade);
  }
  else if ((grade == 'B') || (grade == 'C')) {
    fprintf(stdout, "%c: Well done\n", grade);
  }
  else if (grade == 'D') {
    fprintf(stdout, "%c: You passed\n", grade);
  }
  else if (grade == 'F') {
    fprintf(stdout, "%c: Better try again\n", grade);
  }
  else {
    fprintf(stdout, "%c: Invalid grade\n", grade);
  }

  // exit gracefully
  //
  return 0;
}