// file: lecture_20/example.cc
//

// include files
//
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

// define the main program
//
int main(int argc, char** argv) {

  /*
  // check the number of arguments
  //
  if (argc < 2) {
    fprintf(stdout, "%s: insuffficient number of arguments (%d)\n",
	    argv[0], argc);
    exit(-1);
  }
  else if (argc == 2) {
    fprintf(stdout, "%s: it is a wonderful day (%d)\n", argv[0], argc);
  }
  else if ((argc == 3) && (strcmp(argv[2], "alex") == (int)0)) {
    fprintf(stdout, "%s: it must be Friday (%d) (%s)\n",
	    argv[0], argc, argv[2]);
  }
  else {
    fprintf(stdout, "%s: not sure why this is happening\n", argv[0]);
  }
  */
  
  // grab the first character of argv[1]
  //
  char grade = argv[1][0];
  fprintf(stdout, "the input was: %c [%d]\n", grade, grade);

  // convert the input to uppercase
  //
  char tmp_grade = toupper(grade);

  // test for its value using if/else if
  //
  fprintf(stdout, "using if/else if:\n");

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

  // switch statement
  //
  fprintf(stdout, "using switch:\n");

  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);
  }


  // try a number
  //
  tmp_grade = atoi(argv[1]);

  switch(tmp_grade) {
  case 3:
    fprintf(stdout, "the perfect number...\n");
    break;
  case 27:
    fprintf(stdout, "my favorite number...\n");
    break;
  default:
    fprintf(stdout, "what is wrong with you!...\n");
  }

  // exit gracefully
  //
  return 0;
}