Completed exercise 1-13, with a bonus version that trades an extra 4 bytes in memory for an equally miniscule perfomance gain at execution.

KNR C/ex1_13_improved.c

@@ -0,0 +1,78 @@
+#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 > 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;
+}