Exercise 3-3: working with a-z and A-Z

3-3.c

@@ -0,0 +1,57 @@
+# include <stdio.h>
+# include <string.h>
+# include <assert.h>
+
+/*
+ * Write a functiona expand(s1, s2) that expands shorthand
+ * notations like a-z in the string s1 into the equivalent
+ * complete list abc...xyz in s2. Allow for letters of either
+ * case and digits and be prepared to handle cases like a-b-c
+ * and a-z0-9 and -a-z. Arrange that a leading or trailing -
+ * is taken literally.
+ */
+
+# define MAXSTRINGLENGTH 1000
+
+void expand(char s1[], char s2[]);
+
+void assert_equal(char expected[], char got[]) {
+    int length_expected = strlen(expected), length_got = strlen(got);
+
+    assert(length_expected == length_got);
+    int i;
+
+    for (i = 0; i < length_expected; i++) {
+        assert(expected[i] == got[i]);
+    }
+}
+
+void test_expand_a_z() {
+    char s1[MAXSTRINGLENGTH] = "a-z", s2[MAXSTRINGLENGTH];
+    expand(s1, s2);
+    assert(26 == strlen(s2));
+    assert_equal("abcdefghijklmnopqrstuvwxyz", s2);
+}
+
+void test_expand_A_Z() {
+    char s1[MAXSTRINGLENGTH] = "A-Z", s2[MAXSTRINGLENGTH];
+    expand(s1, s2);
+    assert(26 == strlen(s2));
+    assert_equal("ABCDEFGHIJKLMNOPQRSTUVWXYZ", s2);
+}
+
+int main (int argc, char const* argv[]) {
+    test_expand_a_z();
+    test_expand_A_Z();
+    return 0;
+}
+
+void expand(char s1[], char s2[]) {
+    int i, c;
+
+    for (i = 0, c = s1[0]; c <= s1[2]; i++, c++) {
+        s2[i] = c;
+    }
+
+    s2[i] = '\0';
+}