1.19

The C Programming Language/1.19.c

@@ -0,0 +1,48 @@
+#include <stdio.h>
+
+#define MAXLINE 10
+
+int _getline(char line[], int maxline);
+void reverse(char to[], char from[], int from_head);
+
+main()
+{
+	int len;
+	char line[MAXLINE];
+	char reversed[MAXLINE];
+
+	while ((len = _getline(line, MAXLINE)) > 0)
+	{
+		reverse(reversed, line, len);
+		printf("%s\n", reversed);
+	}
+
+	return 0;
+}
+
+int _getline(char s[], int lim)
+{
+	int c, i, j;
+	for (i = 0; (c = getchar()) != '\n'; ++i)
+	{
+		if (i < lim - 1)
+			s[i] = c;
+	}
+
+	j = i;
+	if (j > lim - 1)
+		j = lim - 1;
+	s[j] = '\0';
+	return j - 1;
+}
+
+void reverse(char to[], char from[], int from_head)
+{
+	int i;
+	for (i = 0; i <= (from_head / 2); ++i)
+	{
+		to[i] = from[from_head - i];
+		to[from_head - i] = from[i];
+	}
+	to[from_head+1] = '\0';
+}