Exercise 1-18. Remove trailing blanks and tabs

14-char-arrays.c

@@ -1,25 +1,33 @@
 #include <stdio.h>
 #define MAXLINE 1000 /* maximum input line size */
+#define MINLINE 81
 
 int getline(char line[], int maxline);
 void copy(char to[], char from[]);
+void trim(char line[], int len);
 
 /* print longest input line */
 main()
 {
 	int len;
 	int max;
+	int c;
 	char line[MAXLINE];
 	char longest[MAXLINE];
 
 	max = 0;
-	while((len = getline(line, MAXLINE)) > 0)
-		if (len > max) {
-			max = len;
-			copy(longest, line);
+	while((len = getline(line, MAXLINE)) > 0) {
+		if (line[len-1] != '\n') {
+			while ((c=getchar())!=EOF && c!='\n')
+				++len;
+			if (c == '\n')
+				++len;
 		}
-	if (max > 0)
-		printf("%s", longest);
+		if (len >= MINLINE) {
+			trim(line, len);
+			printf("%s", line);
+		}
+	}
 	return 0;
 }
 
@@ -47,3 +55,15 @@ void copy(char to[], char from[])
 	while ((to[i] = from[i]) != '\0')
 		++i;
 }
+
+/* trim: remove extraneous blanks and tabs */
+void trim(char s[], int len)
+{
+	int i;
+
+	for (i = len-2; i >= 0; --i)
+		if (s[i] == ' ' || s[i] == '\t')
+			s[i] = '\0';
+		else
+			return;
+}