Beginner question regarding switch statements with arrays....

Question

Doing a little project for my beginner's object oriented programming course. I've written the following code, but the switch statement won't recognize my array values....I'm required to use a switch statement in my program, which will count various character types in an external file....any insight is appreciated.
import java.io.*;
public class MyProg
  public static BufferedReader inFile;
  public static void main(String[] args)
    throws IOException, StringIndexOutOfBoundsException
    String line;
    inFile = new BufferedReader(new FileReader("TME5Part1.dat3"));
      char UpperCase[]= {'A','B','C','D','E','F','G','H','I','J','K','L','M',
                                      'N','O','P','Q','R','S','T','U','V','W','X','Y','Z'};          
      char LowerCase[]=     {'a','b','c','d','e','f','g','h','i','j','k','l','m',
                                      'n','o','p','q','r','s','t','u','v','w','x','y','z'};
      char Digit[]= {'0','1','2','3','4','5','6','7','8','9'};
      char EndMark[]= {'!','.','?'};
      char MidMark[]= {',',':',';'};
    char symbol;                                                            
    int upperCaseCt = 0;                                             
    int lowerCaseCt = 0;
    int digitCt = 0;
    int endMarkCt = 0;
    int midMarkCt = 0;
      int spaceCt = 0;
      int otherCharCt = 0;
    line = inFile.readLine();          //read first line (priming read)
    while (line != null)               // Loop until end of data (empty line)
      for (int count = 0; count < line.length(); count++)  // Loop until end of line
        symbol = line.charAt(count);                    
            for (int i=0; i<=25;i++)                              
                    char uppercase=UpperCase;               //get array values for i
                    char lowercase=LowerCase[i];
                    if (i<=9) {char digit=Digit[i];}               
                    if (i<=2) {     char endmark=EndMark[i];     
                                        char midmark=MidMark[i];
                    switch(symbol)                                             
                              case uppercase : upperCaseCt++;
                                        break;
                              case lowercase : lowerCaseCt++;
                                             break;
                              case digit          : digitCt++;
                                             break;
                              case endmark     : endMarkCt++;
                                             break;
                              case midmark     : midMarkCt++;
                                             break;
                              case ' '          : spaceCt++;
                                             break;
                              default          : otherCharCt++;
                                             break;
          line = inFile.readLine();                                   
     System.out.println("Number of uppercase letters = "+upperCaseCt);               
     System.out.println("Number of lowercase letters = "+lowerCaseCt);
     System.out.println("Nubmer of digits = "+digitCt);
     System.out.println("Number of end punctuation marks = "+endMarkCt);
     System.out.println("Number of mid punctuation marks = "+midMarkCt);
     System.out.println("Number of spaces = "+spaceCt);
     System.out.println("Number of other characters = "+otherCharCt);
I was trying to do it this way rather than "case 'A':
case 'B':
case 'Z:" for each type of 'symbol'.
Unfortunately, the switch statement is required or this would be easier with arrays and for loops...I'm not sure if my code is even possible. Thanks in advance =)
Edited by: RiTarDid

Answer 1

RiTarDid wrote:
For sure it is the most straightforward way, but my curiosity is getting the better of me....I will most likely submit the program with the longer (value-by-value) switch method, as I haven't found anyone who can tell me how to properly reference an array value in a 'case'.Well, you can do this (basically):
switch(some_array[some_index]) {
    case 'a':  blahblah
    case 'z':  blahblah
}What you can't do is this:
switch(some_scalar_value) {
  case a_whole_array:  blahblah
  case a_whole_another_array: blahblah
}Because the latter isn't what "case" means.
If you want to do something like the latter, use if/else statements. Here's a dirty little industry secret: people seldom use switch/case. if/else is a lot more common.
Actually that dirty little secret isn't really particular dirty or particularly secret. It is, however, little.
I just recall a suggestion to use arrays for any group that is more than 10 values in size;Well...sort of...
You should use the expression of data that's appropriate for what the data is. If it's a collection of data of the same kind and an ordering, then an array or a java.util.List makes sense. If it's data that is of the same kind but no ordering and no duplicates are allowed, use a java.util.Set. (Etc. on this front.) If it's a collection of un-alike data, but which belongs in associated groups (e.g., a user's name, age, height, and whether s/he's married) then you should create a class that represents that logical grouping. Etc. If you have more than 10 individual data that can't be grouped or collected somehow, then chances are you need to rethink what's happening.
so I wanted to see if an array could be employed for comparisons with the 'switch' statement. The program is simple enough, I'm just trying to flex my problem-solving muscle in different ways. :)
thanks for replying, hope I can get a definite "yes, it can be done this way" or "no it can't" if there's anyone out there who knows.....The problem is that your example is contrived. So you can do a variety of things that fit into the contrivance, but they'd be weird things.
In practice, you'd want to use the character classification methods in Character, if you wanted to characterize a bunch of characters. Or maybe a regular expression. There's no need to keep an array of characters to match against if you want to determine whether a particular character is upper case. In fact, that's the wrong way of doing things, because Character.isUpperCase is more likely to tell whether any character (not just stuff that's also an element of ASCII) qualifies as upper case.