Help with alphabetic to numeric

This is a discussion on Help with alphabetic to numeric within the C Programming forums, part of the General Programming Boards category; OK..guys this one has really stumped me!! I tried going through the logic and using a switch function, but I ...

  1. #1
    Registered User
    Join Date
    Oct 2003
    Posts
    49

    Help with alphabetic to numeric

    OK..guys this one has really stumped me!! I tried going through the logic and using a switch function, but I have been getting some crazy outputs. Plus I have to incorporate a "toupper" function inside it. Is that correct place?

    **NOTE: I can not use strings or anything else, b/c we have not learned them yet.**

    Code:
    #include <stdio.h>
    #include <ctype.h>
    
    main()
    {
    
    char ch;
    int i = 0;
    
    printf("Enter a phone number: ");
    while ( ch = getchar() != '\n' );
    
    ch = toupper(ch);	
    	
    switch ( ch ) {
    
    	case 'A': case 'B': case 'C':
    	i = 2;
    	break;
    
    	case 'D': case 'E': case 'F':
    	i = 3;
    	break;
    
    	case 'G': case 'H': case 'I':
    	i = 4;
    	break;
    
    	case 'J': case 'K': case 'L':
    	i = 5;
    	break;
    
    	case 'M': case 'N': case 'O':
    	i = 6;
    	break;
    
    	case 'P': case 'R': case 'S':
    	i = 7;
    	break;
    
    	case 'T': case 'U': case 'V':
    	i = 8;
    	break;
    
    	case 'W': case 'X': case 'Y':
    	i = 9;
    	break;
    
    	default:
    		printf("%d", i);
    		break;
    	}
    
    printf("%d", i );
    
    }
    Thanks for any help!

  2. #2
    Guest Sebastiani's Avatar
    Join Date
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    Location
    Waterloo, Texas
    Posts
    5,655
    >> while ( ch = getchar() != '\n' );

    Look at the semicolen at the end of that statement. The loop stops there, as they say.

    Also, to avoid nasty side effects, always form conditionals like the above like:

    Code:
    while ( (ch = getchar()) != '\n' )
    {
     // code
    }

  3. #3
    Been here, done that.
    Join Date
    May 2003
    Posts
    1,157

    Re: Help with alphabetic to numeric

    Originally posted by CrackerJack
    Code:
    ch = toupper(ch);	
    	
    switch ( ch ) {
    can also be written as:

    Code:
    switch (toupper(ch) ) {
    Definition: Politics -- Latin, from
    poly meaning many and
    tics meaning blood sucking parasites
    -- Tom Smothers

  4. #4
    Registered User
    Join Date
    Oct 2002
    Posts
    98
    You also need some extra brackets in your while statement..
    Code:
      while( ( ch = getchar()) != '\n' )
      {
         ...
    I compiled your code without the brackets (but with the other corrections) and still got a load of rubbish out.
    There is no such thing as a humble opinion

  5. #5
    Registered User
    Join Date
    Oct 2003
    Posts
    49
    Yeah...there was a bunch of junk wrong w/ it!!! I sat down w/ my teacher for almost an hour and we finally figured out what was wrong. Using the printf in the default just would not work, so we inserted into the case statements. Doesn't look all that pretty, but it works...

    JOE

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