Fixed a potential bug that would cause a hang on unrecognized input. Added a 39th position to both charCount and printTable for storing, enumerating, and displaying untracked characters that do not fit to a defined position in charCount.

KNR C/ex1_14_improved.c

@@ -11,16 +11,16 @@ int main(){
 	 * 0 or 27 and print a different character that isn't in refTable*/
 	/*TODO find a way to do this so that # and ! are replaced by WSPC and PCTN
 	 * respectively*/
-	int printTable [38] = { '#' , 'a' , 'b' , 'c' , 'd' , 'e' , 'f', 'g' , 'h' ,
+	int printTable [39] = { '#' , 'a' , 'b' , 'c' , 'd' , 'e' , 'f', 'g' , 'h' ,
 	'i' , 'j' , 'k' , 'l' , 'm' , 'n', 'o' , 'p' , 'q' , 'r' , 's' , 't' , 'u' ,
 	'v' , 'w' , 'x' , 'y' , 'z' , '!', '0' , '1'
-	, '2' , '3' , '4' , '5' , '6' , '7' , '8' , '9'};
+	, '2' , '3' , '4' , '5' , '6' , '7' , '8' , '9' , '?'};
 
 	/*Initialize character count storage array. Whitespaces are stored at pos 0
 	 * while letters are stored at their numeric positions in the alphabet, and
 	 * punchtuation is stored at position 27.Numbers are stored at positions
 	 * 28 through 38*/
-	int charCount[38] = { 0 };
+	int charCount[39] = { 0 };
 	int i = 0;
 
 
@@ -37,6 +37,8 @@ int main(){
 			++charCount[a - 64];
 		} else if(a >= 48 && a <= 57) { /*Check for numbers*/
 			++charCount[a - 20];
+		} else {
+			++charCount[38]; /*Catch-all for unrecognized/untracked input*/
 		}
 	}
 	/*Input text enumeration complete; set values in refTable for printing...*/
@@ -50,7 +52,7 @@ int main(){
 	/*Print a histogram of gathered data (recycled from ex1_13_improved.c.*/
 	i = 0;
 	printf("\nHistogram of letters encountered.\n");
-	for (int b = charCount[i]; i <= 37; ++i){
+	for (int b = charCount[i]; i <= 38; ++i){
 		printf ("%1c ", printTable[i]);
 		for (; b > 0; --b){
 			printf("|");