storage.txt is now created at runtime rather than being assumed to be present and empty. recall() now removes storage.txt at completion. main() now includes a check to see whether storage.txt already exists, sends an error message, and exits with code 1 if storage.txt is already present.

KNR C/ex1-16-2.c

@@ -1,4 +1,6 @@
 #include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
 
 void store();
 void enumerate();
@@ -7,6 +9,11 @@ int longest = 0;
 int posLongest = 0;
 
 int main(){
+	if((access("storage.txt",F_OK)) == 0){
+			printf("Error: storage file already exists.");
+			return 1;
+			EXIT_FAILURE;
+	}
 	store();
 	enumerate();
 	recall();
@@ -72,4 +79,5 @@ void recall (){
 		}
 	}
 	fclose (fp);
+	remove("storage.txt");
 }