80 lines
2.8 KiB
C
80 lines
2.8 KiB
C
#include <stdio.h>
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/*Initial implementation of KNR C Exercise 1-14*/
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int main(){
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/*Reference array that stores literal characters to be searched later by a
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* for loop, obtaining their position in the array, and therefore knowing
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* what position to add them to in charCount without needing a special case
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* for every possible character. While it is possible to exploit the ascii
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* table to do this procedurally, this is faster by virtue of initializing
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* at compile time rather than run time*/
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int refTable [27] = { ' ' , 'a' , 'b' , 'c' , 'd' , 'e' , 'f', 'g' , 'h' ,
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'i' , 'j' , 'k' , 'l' , 'm' , 'n', 'o' , 'p' , 'q' , 'r' , 's' , 't' , 'u' ,
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'v' , 'w' , 'x' , 'y' , 'z'};
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/*Initialize an array of labels for the numerical table later. This looks
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* wierd since it's mostly refTable[] again, but again, we do this at
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* copile rather than procedurally in order to avoid adding an extra if
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* statement on the print loop to look for the specific case where i is
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* 0 or 27 and print a different character that isn't in refTable*/
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/*TODO find a way to do this so that # and ! are replaced by WSPC and PCTN
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* respectively*/
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int printTable [28] = { '#' , 'a' , 'b' , 'c' , 'd' , 'e' , 'f', 'g' , 'h' ,
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'i' , 'j' , 'k' , 'l' , 'm' , 'n', 'o' , 'p' , 'q' , 'r' , 's' , 't' , 'u' ,
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'v' , 'w' , 'x' , 'y' , 'z' , '!'};
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/*Initialize character count storage array. Whitespaces are stored at pos 0
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* while letters are stored at their numeric positions in the alphabet, and
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* punchtuation is stored at position 27.*/
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int charCount[28] = { 0 };
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int i = 0;
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/*Begin input text enumeration loop...*/
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for(int a = getchar(); a != EOF; a = getchar()){
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/*Begin whitespace filter check*/
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if(a == '\n' || a == ' ' || a == '\t'){
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++ charCount[0];
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continue; /*Escape and restart loop to avoid running redundant
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tests.*/
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}
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/*Begin refTable search loop; check if a = current pos in the refTable
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* array, increment that position in charCount[], otherwise, increment
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* i and check again. In any case, break on condition met or value i
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* out of expected range.*/
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for(i = 1; i <= 27; ++i){
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if(a == refTable[i]){
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++charCount[i];
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break;
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} else if(i == 27){
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++charCount[27]; /*Increments charCount[27] on unspecified char
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thus preventing hangs on unspecified input*/
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break;
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}
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}
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}
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/*Input text enumeration complete; set values in refTable for printing...*/
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/*Begin output generation...*/
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/*Vertical table of numerical values:*/
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for(int i=0; i <= 27; ++i)
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printf("%4c %4d\n", printTable[i], charCount[i]);
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/*Print a histogram of gathered data (recycled from ex1_13_improved.c.*/
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i = 0;
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printf("\nHistogram of letters encountered.\n");
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for (int b = charCount[i]; i <= 27; ++i){
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printf ("%1c ", printTable[i]);
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for (; b > 0; --b){
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printf("|");
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}
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printf("\n");
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b = charCount[(i + 1)];
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}
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return 0;
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}
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