first commit!

longest_line_extern.c

@@ -0,0 +1,47 @@
+#include <stdio.h>
+#define MAXLINE 1000
+
+int max_len;
+char current_line[MAXLINE];
+char longest[MAXLINE];
+
+int getlime();
+void copy();
+
+int main() {
+  int current_len;
+  extern int max_len;
+  extern char longest[];
+
+  max_len = 0;
+  while ((current_len = getlime()) > 0)
+    if (current_len > max_len) {
+      max_len = current_len;
+      copy();
+    }
+  if (max_len > 0) /* there was some line */
+    printf("%s", longest);
+
+  return 0;
+}
+
+int getlime() {
+  int ch, i;
+  extern char current_line[];
+
+  for (i = 0; i < MAXLINE - 1 && (ch = getchar()) != EOF && ch != '\n'; ++i)
+    current_line[i] = ch;
+  if (ch == '\n') {
+    current_line[i] = ch;
+    ++i;
+  }
+  current_line[i] = '\0';
+  return i;
+}
+
+void copy() {
+  extern char current_line[], longest[];
+
+  for (int i = 0; (longest[i] = current_line[i]) != '\0'; ++i)
+    ;
+}