feat: (cstr) strcount

lib/cstr.c

@@ -60,3 +60,16 @@ strtrimr (char *str)
 
     return i;
 }
+
+size_t
+strcount (const char *str, char c)
+{
+    size_t count;
+
+    count = 0;
+    while (*str)
+        if (*str++ == c)
+            count += 1;
+    
+    return count;
+}

lib/inc/cstr.h

@@ -6,5 +6,6 @@
 char *strtrim (char *str); /* trim whitespace of a cstring (both beginning and end) */
 char *strtriml (char *str); /* trim whitespace of a cstring on the left (beginning of string). */
 size_t strtrimr (char *str); /* trim whitespace of a cstring on the right (end of string) */
+size_t strcount (const char *str, char c);
 
 #endif // CUTILS_CSTR_H_

test/main.c

@@ -29,6 +29,11 @@ test_cstr (void)
     test_add (&suite, test_assert_op (sn, ==, s2 + 4), "strtrim pointer");
     test_add (&suite, test_assert_op (strlen (s2), ==, 17), "strtrim original pointer length");
     test_add (&suite, test_assert_op (strlen (sn), ==, 13), "strtrim new pointer length");
+
+    char *s3 = "Hello, World!\n";
+    test_add (&suite, test_assert_op (strcount (s3, 'l'), ==, 3), "strcount multiple occurances");
+    test_add (&suite, test_assert_op (strcount (s3, '\n'), ==, 1), "strcount one occurance");
+    test_add (&suite, test_assert_op (strcount (s3, 'X'), ==, 0), "strcount no occurance");
     
     return test_suite_get_results (&suite);
 }