Skeleton of exercise 1-16; functionally a verbatim copy of the example text on page 30 of KNR C, though in reality, I have made it more readable and fixed a couple of bugs related to expanded functionality of modern C.

KNR C/ex1_16.c

@@ -0,0 +1,71 @@
+#include <stdio.h>
+
+/*A program for finding the longest line in its input, and then returning the
+ * longest. Primarily copied from page 30 of KNR C by Kernigham Ritchie.
+ * Annotation is extremely verbose so that I could break this code down for
+ * myself in a way that made more sense than as-written.*/
+
+#define MAXLINE 1000 //Define maximum allowable line length.
+
+//Forward declaration for a function that will retreive the current line and
+//store it in array line[]. Since modern C actually has a getline function, we
+//declare this as pullline
+int pullLine(char line[], int maxline);
+//Forward declaration for a function to copy between arrays.
+void copy(char from[], char to[]);
+
+int main(){
+
+	//Declare ints related to tracking line lengths.
+	int currentLength; //Length of current line; originally len.
+	int max = 0; //Length of longest line encountered; originally max.
+					 //Initialized as 0 as opposed to using a separate
+					 //statement to set value as in original code.
+
+	char line[MAXLINE]; //Initialize array for storing current line.
+	char longest [MAXLINE]; //Initialize array for storing longest line so far.
+	
+	while ((currentLength = pullLine(line, MAXLINE)) > 0){
+		if (currentLength > max){
+			max = currentLength;
+			copy(line, longest);
+		}
+	}
+	if (max > 0) //If any lines were encountered, print the longest.
+		printf("%s", longest);
+	return 0;
+}
+
+//pullLine will read a line into array s[] and return its length.
+int pullLine(char s[], int lim){
+	int c, i;
+	/*Set i= 0, check if i is < lim, which is MAXLINE as written AND that
+	 * getchar returns a non EOF character (while stepping c) AND that the 
+	 * character pulled (c), is not a newline character, then increment i. The
+	 * actual body of this loop simply stores the value of the retrieved 
+	 * character in array s[] at position |i|.*/
+	for (i = 0; i < lim-1 && (c=getchar())!=EOF && c!='\n'; ++i)
+		s[i] = c;
+
+	if (c == '\n'){ //If |c| is \n, then still set pos \i\ in array s[] and 
+					//increment i. This has to be handled outside the for loop,
+					//since c =='\n' is a break condition.
+		s[i] = c;
+		++i;
+	}
+	s[i] = '\0'; //Set a null value at the end of the line for termination.
+	return i; //Return the length of the line pulled.
+}
+
+//Function for copying one array to another. I chose to write this as
+//from -- > to instead of to --> from because it's not the 90s any more and 
+//I feel like I'm allowed to have a little temporal linearity as a treat.
+void copy(char from[], char to[]){
+	int i = 0; //I have once again initialized and declared in the same line
+			   //because it is 2025.
+
+	//Set the value of pos \i\ in to[] to the value of pos \i\ in from as long
+	//as it is not null.
+	while ((to[i] = from[i]) != '\0')
+		++i;
+}