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Reading file input into an array

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Reading file input into an array

 
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  #1
Mar 25th, 2007
I am trying to read file input into an array so I can tally up the number of times each letter appears (including the apostrophe). I am not sure what I am doing wrong, but my file data is not getting assigned to the array outside the function.

C++ Syntax (Toggle Plain Text) 
  1. #include<iostream>
  2. using std::cin;
  3. using std::cout;
  4. using std::endl;
  5. //using::left;
  6. //using::right;
  7. using std::istream;
  8. using std::ostream;
  9. #include<string>
  10. using std::getline;
  11. #include<iomanip>
  12. using std::setw;
  13. //#include <cstdlib>
  14. //#include <ctime>
  15. #include<cstring>// prototype for strtok, strlen, strcmp, strncmp, strcpy, strncpy, strcat, strncat
  16. using std::string;
  17. #include<cctype>
  18. #include<fstream>
  19. using std::fstream;
  20. using std::ifstream;
  21. using std::ofstream;
  22. // prototypes
  23. //int readData( char *, char * );
  24. int readData( char *, char *, int [ ]);
  25. void tokenizeData( char *, char * );
  26. constchar apostrophe = '\'';
  27. char *tokenPtr;
  28. /*
  29. // initialize alaphabet array
  30. const char *alphabet[ 27 ] = { '\'', 'A', 'B', 'C', 'D', 
  31. 'E', 'F', 'G', 'H', 'I', 
  32. 'J','K', 'L', 'M', 'N', 
  33. 'O','P', 'Q', 'R', 'S', 'T',
  34. 'U', 'V', 'W', 'X', 'Y', 'Z', '\0' };
  35. */
  36. //------------------------------------------------------------------------------
  37. int main()
  38. {
  39. /*
  40. // initialize alaphabet array
  41. char alphabet[ 28 ] = { '\'', 'A', 'B', 'C', 'D', 
  42. 'E', 'F', 'G', 'H', 'I', 
  43. 'J','K', 'L', 'M', 'N', 
  44. 'O','P', 'Q', 'R', 'S', 'T',
  45. 'U', 'V', 'W', 'X', 'Y', 'Z', '\0' };
  46. */
  47. int letterTotals[ 28 ] = { 0 };
  48.  
  49. int numberOfWords;
  50. //int numberOfTokenizedWords;
  51. //ifstream myInFile( "data.txt" );
  52. char *myInFile = ( "data.txt" );
  53. char *wordArray = { 0 };
  54. //char *tokenizedWordArray = { 0 };
  55. //numberOfWords = readData( myInFile, wordArray );
  56. numberOfWords = readData( myInFile, wordArray, letterTotals );
  57. //cout << "\nnumberOfWords = " << numberOfWords;
  58. for( int index = 0; index < numberOfWords; index++ )
  59. { 
  60. cout << "----------------------------" << wordArray[ index ] << "\n";
  61. //cout << wordArray[ index ] << "\n";
  62. }
  63.  
  64. /*
  65. numberOfTokenizedWords = tokenizeData( myInFile, tokenizedWordArray );
  66. //cout << "\nnumberOfTokenizedWords = " << numberOfTokenizedWords;
  67. for( int index = 0; index < numberOfTokenizedWords; index++ )
  68. { 
  69. cout << "----------------------------" << tokenizedWordArray[ index ] << "\n";
  70. //cout << tokenizedWordArray[ index ] << "\n";
  71. }
  72. */
  73. return 0;
  74. }
  75. //------------------------------------------------------------------------------
  76. //int readData( char *dataFileName, char *wWordArray /*int letterTotals[ ] */)
  77. int readData( char *dataFileName, char *wWordArray, int letterTotals[ ] )
  78. {
  79. int wordCount = 1;
  80. char currentLetter;
  81. ifstream wMyInFile( dataFileName );
  82. int letterIndex = 0;
  83.  
  84. /*
  85. if( wMyInFile.eof() ) // if no words exist in file
  86. {
  87. return 0;
  88. }
  89. */
  90.  
  91. wWordArray = new char;
  92. int counter = 0;
  93. while( !wMyInFile.eof() )
  94. {
  95. currentLetter = wMyInFile.peek(); // look at first letter
  96.  
  97. tolower( currentLetter );
  98. while( isalpha( currentLetter ) || ( currentLetter == apostrophe ) )
  99. { 
  100. //letterTotals[ wordCount ] += wMyInFile.get();
  101. //letterTotals[ counter ];
  102. cout << "\n\ncurrent letter = " << currentLetter << "\n\n"; 
  103. wWordArray[ wordCount ] += wMyInFile.get( ); // store letter in array
  104. currentLetter = wMyInFile.peek(); // look at the next char 
  105. switch( currentLetter )
  106. {
  107. case '\'': letterTotals[ 0 ]++;
  108. break;
  109. case 'a':
  110. case 'A': letterTotals[ 1 ]++;
  111. break;
  112. case 'b': 
  113. case 'B': letterTotals[ 2 ]++;
  114. break;
  115. case 'c': 
  116. case 'C': letterTotals[ 3 ]++;
  117. break;
  118. case 'd': 
  119. case 'D': letterTotals[ 4 ]++;
  120. break;
  121. case 'e': 
  122. case 'E': letterTotals[ 5 ]++;
  123. break;
  124. case 'f': 
  125. case 'F': letterTotals[ 6 ]++;
  126. break;
  127. case 'g': 
  128. case 'G': letterTotals[ 7 ]++;
  129. break;
  130. case 'h': 
  131. case 'H': letterTotals[ 8 ]++;
  132. break;
  133. case 'i': 
  134. case 'I': letterTotals[ 9 ]++;
  135. break;
  136. case 'j': 
  137. case 'J': letterTotals[ 10 ]++;
  138. break;
  139.  
  140. case 'k': 
  141. case 'K': letterTotals[ 11 ]++;
  142. break;
  143. case 'l': 
  144. case 'L': letterTotals[ 12 ]++;
  145. break;
  146. case 'm': 
  147. case 'M': letterTotals[ 13 ]++;
  148. break;
  149. case 'n': 
  150. case 'N': letterTotals[ 14 ]++;
  151. break;
  152. case 'o': 
  153. case 'O': letterTotals[ 15 ]++;
  154. break;
  155. case 'p': 
  156. case 'P': letterTotals[ 16 ]++;
  157. break;
  158. case 'q': 
  159. case 'Q': letterTotals[ 17 ]++;
  160. break;
  161. case 'r': 
  162. case 'R': letterTotals[ 18 ]++;
  163. break;
  164. case 's': 
  165. case 'S': letterTotals[ 19 ]++;
  166. break;
  167. case 't': 
  168. case 'T': letterTotals[ 20 ]++;
  169. break;
  170. case 'u': 
  171. case 'U': letterTotals[ 21 ]++;
  172. break;
  173. case 'v': 
  174. case 'V': letterTotals[ 22 ]++;
  175. break;
  176. case 'w': 
  177. case 'W': letterTotals[ 23 ]++;
  178. break;
  179. case 'x': 
  180. case 'X': letterTotals[ 24 ]++;
  181. break;
  182. case 'y': 
  183. case 'Y': letterTotals[ 25 ]++;
  184. break;
  185. case 'z': 
  186. case 'Z': letterTotals[ 26 ]++;
  187. break;
  188. default: break;
  189. }
  190. char letterValue = 44;
  191. cout << "letter: " << letterValue << "\n\n";
  192. int index = 0;
  193. cout << "letterTotals[ " << index << " ] = " << letterTotals[ index ] << "\n";
  194. letterValue = 65;
  195. for( index = 1; index < 27; index++ )
  196. {
  197. cout << "letter: " << letterValue << "\n";
  198. cout << "letterTotals[ " << index << " ] = " << letterTotals[ index ] << "\n\n";
  199. letterValue++;
  200. }
  201. }
  202.  
  203. counter++;
  204. wWordArray[ wordCount ] = '\0';
  205. //letterIndex = 0;
  206. cout << "\n----- wordCount = " << wordCount << " -----\n\n";
  207.  
  208. while( !isalpha( currentLetter ) && ( currentLetter != apostrophe ) )
  209. {
  210. wMyInFile.ignore( 1 );
  211. currentLetter = wMyInFile.peek(); // look at the next char
  212. }
  213.  
  214. wordCount++;
  215. wWordArray = new char;
  216. }
  217. return wordCount;
  218. }
  219. //------------------------------------------------------------------------------
  220. void tokenizeData( char *dataFileName, char *wTokenizedWordArray )
  221. {
  222. int tokenizedWordCount = 1;
  223. cout << "\nThe string to be tokenized is:\n " << wTokenizedWordArray
  224. << "\n\nThe tokens are: \n\n";
  225. // begin tokenization of sentence
  226. tokenPtr = strtok( wTokenizedWordArray, " " );
  227. // continue tokenizing sentence until tokenPtr becomes NULL
  228. while( tokenPtr != NULL )
  229. {
  230. cout << tokenPtr << '\n';
  231. tokenPtr = strtok( NULL, " " ); // get next token
  232. tokenizedWordCount++;
  233. }
  234. cout << "\nAfter strtok, sentence = " << wTokenizedWordArray << endl;
  235. //cout << "\nnumberOfTokenizedWords = " << numberOfTokenizedWords;
  236. for( int index = 0; index < tokenizedWordCount; index++ )
  237. { 
  238. cout << "*************" << wTokenizedWordArray[ index ] << "\n";
  239. //cout << tokenizedWordArray[ index ] << "\n";
  240. }
  241. //return tokenizedWordCount;
  242. }
Last edited by WaltP; Mar 25th, 2007 at 7:51 am.
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Re: Reading file input into an array

 
0
  #2
Mar 25th, 2007
Sheesh! Why do you make it so complicated?

Take a look at the ASCII table. Each letter has in fact a numeric value. So use this to your advantage. Create an int array of 128 elements, as there are 128 characters in ASCII. Now look how easy it is:
c Syntax (Toggle Plain Text) 
  1. lookupTable['a']++;

That simply increments the value of 'a', which happens to be the value 97. So if you want to make it simple, just loop through the string, and plug each letter into the array and increment that element. Then all you have to do is print out the elements in the array, and you're done.

Also see this for why eof is bad.
"Technological progress is like an axe in the hands of a pathological criminal."
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Re: Reading file input into an array

 
0
  #3
Mar 25th, 2007
it is much easier if u use the c++ std library.

C++ Syntax (Toggle Plain Text) 
  1. #include <iostream>
  2. #include <fstream>
  3. #include <iterator>
  4. #include <map>
  5. #include <algorithm>
  6. #include <cctype>
  7. using namespace std;
  8.  
  9. struct print_it
  10. {
  11.    inline void operator() ( const pair<char,int>& p ) const
  12.    { cout << p.first << " occurs " << p.second << " times\n" ; }
  13. };
  14.  
  15. int main()
  16. {
  17.    const char* const file_name = "data.txt" ;
  18.    ifstream file(file_name) ;
  19.    if( !file ) return 1 ;
  20.    const char apostrophe = '\'' ;
  21.    map<char,int> char_cnt ;
  22.    char c ;
  23.    while( (file>>c) && ( isalpha(c) || (c==apostrophe) ) ) ++char_cnt[c] ;
  24.    for_each( char_cnt.begin(), char_cnt.end(), print_it() ) ;
  25.    return 0 ;
  26. }
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