coded + unit tested

Author: Ram swaroop

src/me/ramswaroop/strings/SubString.java

@@ -0,0 +1,44 @@
+package me.ramswaroop.strings;
+
+/**
+ * Created by IntelliJ IDEA.
+ *
+ * @author: ramswaroop
+ * @date: 10/20/15
+ * @time: 1:15 PM
+ */
+public class SubString {
+
+    /**
+     * Naive approach to determine whether string {@param s2} is a
+     * substring of string {@param s1}.
+     *
+     * @param s1
+     * @param s2
+     * @return
+     */
+    public static boolean isSubString(String s1, String s2) {
+        char[] c1 = s1.toCharArray(),
+                c2 = s2.toCharArray();
+        int l1 = c1.length,
+                l2 = c2.length,
+                i, j;
+
+        for (i = 0; i <= l1 - l2; i++) {
+            for (j = 0; j < l2 && i + j < l1; j++) {
+                if (c1[i + j] != c2[j]) break;
+            }
+            if (j == l2) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    public static void main(String a[]) {
+        System.out.println(isSubString("ramswaroop", "ram"));
+        System.out.println(isSubString("ramswaroop", "rams"));
+        System.out.println(isSubString("ramswaroop", "ramss"));
+        System.out.println(isSubString("ramswaroop", "ar"));
+    }
+}