Project-Scylla/KNR C/ex1_13_improved.c

#include <stdio.h>

/*Slight modification to ex1_13.c that makes charCount an array of ints 11
 * entries long, in order to circumvent the need for additional mathematical
 * operations down the line as a consequence of ocurrences of the value "1"
 * being store at position 0. This sacrifices 4 bytes of memory in the stack
 * by extending the array, but results a shorter binary.
 *
 * how much shorter, you ask?
 *
 * 1 instruction.
 *
 * lol.*/

#define IN 1 /*State when selected character is within a word*/
#define OUT 0 /*State when selected character is any kind of whitespace*/



int main(){

	int charCount[11]; /*Array for storing char lengths*/

	int last, lCount, state, i; /*last stores last character, or 0 at init.
								  lCount increments every time the main for
								  loop encounters a non-newline/whitespace
								  character and then resets when one is
								  encountered after commiting its value
								  to charCount.*/
	/*Begin array initialization*/
	for(i = 0; i < 11; ++i){
		charCount[i] = 0;
		}
	/*End array init*/
	

	last = lCount = 0;
	
	/*Begin input letter count enumeration.*/
	for(int a = getchar(); a != EOF; a = getchar()){

		/*Check if current char is WS. If so, set state to OUT and check if the
		 * last character was not. If it was not, then we are exiting a word,
		 * and so comitting lCount to charCount.*/
		if(a == '\t' || a == ' ' || a == '\n'){ 
			state = OUT;
			if (last != '\t' && last != ' ' && last != '\n'){ /*True on word
																exit only.*/
				if(lCount > 10){ /*Array charCount only stores values up to 10,
								   so we will add any longer words to the
								   column for 10+*/
					++charCount[10]; 
				} else {
					++charCount[(lCount)];				}
				lCount = 0; /*Reset lCount when a condition that dumps it to
							  charCount is triggered*/
			}
		} else { 
			state = IN;
			++lCount; /*Increment lCount when encountering a non-WS
						character.*/
		}
		last = a; 
		}
	/*Input letter count enumeration complete*/
	
	/*Print a table of the number of words encountered for
	 * each number of characters.*/
	printf("Word letter count composition:\n");
	for (i = 1; i <= 9; ++i)
		printf("%3d", (i));
	printf ("%3s", "  10+\n");
	for (i = 1; i <= 10; ++i)
		printf("%3d", charCount[i]);

	/*Print a histogram of gathered data.*/
	printf("\nHistogram of char counts by frequency of words enountered with a given count.\n");
	i = 1; /*Reset value of i, since we're reusing it*/
	for (int b = charCount[i]; i <= 10; ++i){
		if (i < 10){
			printf("%d  ", (i));
		} else if (i == 10) {
			printf("%3s", "10+");
		}

		for (; b > 0; --b){
			printf("|");
		}
		printf("\n");
		b = charCount[(i + 1)]; /*Get the value of the next position in the
								  array; since i hasn't incremented yet,
								  it's i+1*/
	}
	return 0;
}