Counting Occurances of a Character

This is a discussion on Counting Occurances of a Character within the C Programming forums, part of the General Programming Boards category; Hi, I need help trying to do the following: Basically, I am trying to count the occurrences of each character ...

  1. #1
    Registered User
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    Counting Occurances of a Character

    Hi,

    I need help trying to do the following:
    Basically, I am trying to count the occurrences of each character in a text file. I'm reading in line by line, and then in each line, analyzing character by character.

    I'm maintaining an array of the counts.

    The conversion of the character to ascii and then ascii to its proper index is working, but when I try to print out the contents of the array, I'm getting ridiculous numbers. Here's my code:

    Code:
    
    int autoGuess() {
    
    int r, x, size, asciiEquiv;  
    int charCount[26];
    
    
    for (r = 0; r < lineCount ; r ++) /* Outer Loop Reads Line By Line */
    
    {
    
    	for (size = 0; size < sizeof(stringArray[r]); size++) {      /*Inner Loop Reads character by character */
    
    
    		if (isalpha((stringArray[r][size])))
    
    		{
    
    			asciiEquiv = (int)stringArray[r][size];
    		/*	printf("%d " , asciiEquiv); It is converting the characters to their respective ASCII codes properly */
    			place = asciiEquiv - 97; 
    		/*	printf("%d ", place);  Converting to Index Properly */
    		    charCount[place]++;
    			printf("%d " , charCount[place]);  // Something happens here
    			
    
    	    }
    
             
    	
    	}
    
    
    	
    
    }
    
    
    for (x = 0; x < 26 ; x ++) {
    
    //printf("%d ", charCount[x]); 
    	getchar();
    
    
    }
    
    
    }
    Thanks!

  2. #2
    Gawking at stupidity
    Join Date
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    You're never initializing you're array to all 0's. Try this:
    Code:
    int charCount[26] = { 0 };
    If you understand what you're doing, you're not learning anything.

  3. #3
    Registered User
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    Feb 2011
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    Alright, that works !

    Elementary mistake..

    Thanks

  4. #4
    Registered User
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    Code:
    for (size = 0; size < sizeof(stringArray[r]); size++) {      /*Inner Loop Reads character by character */
    Are you sure that you want to use sizeof() here?

  5. #5
    Registered User
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    Why would that be an issue?

  6. #6
    Registered User
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    This is highly dangerous:
    Code:
    place = asciiEquiv - 97; 
    		/*	printf("%d ", place);  Converting to Index Properly */
    		    charCount[place]++;
    You are assuming that all characters are guaranteed to be 'a' to 'z'. That is, lowercase only... not spaces, no special punctuation.
    sizeof(), as was pointed out, will make it loop to the end of each row regardless of whether there is valid data. The rows may contain uninitialized (garbage), or zeroes, which would put your index outside the valid range.

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