Solve Exercise 5-4: strend()

Detailed answers below the question will only occur now if I cannot
explain myself well enough in code and nearby comments. I'm looking
to learn how to write better comments so there's less need for prose.

1 files changed, 37 insertions, 0 deletions

diff --git a/ch5/5-04_strend.c b/ch5/5-04_strend.c
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+++ b/ch5/5-04_strend.c
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+#include <stdio.h>
+#include <string.h>
+
+/* The C Programming Language: 2nd Edition
+ *
+ * Exercise 5-4: Write the function strend(s,t), which returns 1 if the string
+ * t occurs at the end of the string s, and zero otherwise.
+ *
+ * Answer: Check from the end of the string!
+ */
+
+int strend(char *, char *);
+
+int main() {
+	char *foo = "kekt";
+	char *bar = "buckets of kekt";
+	printf("%d\n", strend(bar, foo)); // should output 1
+	foo = "missile";
+	bar = "Did you see those missiles?!";
+	printf("%d\n", strend(bar, foo)); // should output 0
+	return 0;
+}
+
+int strend(char *s, char *t) {
+	// Go to the end of s
+	while (*s != '\0') {
+		s++;
+	}
+	// back up s by however long t is
+	s -= strlen(t);
+	// Check to be sure the rest of the string matches
+	for (; *s == *t && *s != '\0' && *t != '\0'; s++, t++);
+	if (*s == '\0' && *t == '\0') {
+		return 1;
+	}
+	return 0;
+}