diff --git a/ch_04/exercise_04-01/compile.sh b/ch_04/exercise_04-01/compile.sh
new file mode 100755
index 0000000..5593686
--- /dev/null
+++ b/ch_04/exercise_04-01/compile.sh
@@ -0,0 +1,5 @@
+#!/bin/bash
+
+
+
+gcc main.c kstrindex.c -I. -std=gnu99 -o a.out
diff --git a/ch_04/exercise_04-01/kstrindex.c b/ch_04/exercise_04-01/kstrindex.c
new file mode 100644
index 0000000..dd95488
--- /dev/null
+++ b/ch_04/exercise_04-01/kstrindex.c
@@ -0,0 +1,34 @@
+#include <stdio.h>
+
+#include "kstrindex.h"
+
+
+int KStrIndex_strindex(char s[], char t[])
+{
+    // Defaults to negative
+    int result = -1;
+    int i = 0, k = 0;
+    int j = 0;
+
+    for (i = 0; s[i] != '\0'; ++i)
+    {
+        for (j = i, k = 0; t[k] != '\0'; ++j, ++k)
+        {
+            if (s[j] != t[k])
+            {
+                break;
+            }
+        }
+
+        // Found starting index of t in s. As the look continues,
+        // there is a check to see if the string matches. This
+        // ensures that the right-most index is found.
+        if (k > 0 && t[k] == '\0')
+        {
+            result = i;
+        }
+    }
+
+
+    return result;
+}
diff --git a/ch_04/exercise_04-01/kstrindex.h b/ch_04/exercise_04-01/kstrindex.h
new file mode 100644
index 0000000..e5d6bc4
--- /dev/null
+++ b/ch_04/exercise_04-01/kstrindex.h
@@ -0,0 +1,7 @@
+#include <stdlib.h>
+
+
+// Returns the right most index of t found in s.
+// Returns -1 if t is not found in s.
+int KStrIndex_strindex(char s[], char t[]);
+
diff --git a/ch_04/exercise_04-01/main.c b/ch_04/exercise_04-01/main.c
new file mode 100644
index 0000000..0ce0e21
--- /dev/null
+++ b/ch_04/exercise_04-01/main.c
@@ -0,0 +1,39 @@
+/*
+ *
+ * Exercise 4-1. Write the function strindex(s,t) which returns the position
+ * of the rightmost occurrence of t in s, or -1 if there is none
+ *
+ * Author: Kun Deng
+ */
+
+#include <stdio.h>
+#include <float.h>
+
+#include <kstrindex.h>
+
+#define ARRAY_SIZE 99900000
+
+int main()
+{
+    char s[] = "this is not the end, but it might as well be.The time is nigh. The end will befall all of us. The end.\0";
+    char t[] = "end\0";
+
+    printf("Searching for string: %s\nIn: %s\n", t, s);
+
+    const int index = KStrIndex_strindex(s, t);
+
+    if (index == -1)
+    {
+        printf("String %s was not found\n", t);
+
+        return -1;
+    }
+
+    printf("String: %s\n", s);
+    printf("Sub String: %s\n", t);
+    printf("Index %d\n", index);
+
+    return 0;
+}
+
+
diff --git a/ch_04/main_template.c b/ch_04/main_template.c
new file mode 100644
index 0000000..bc72931
--- /dev/null
+++ b/ch_04/main_template.c
@@ -0,0 +1,14 @@
+/*
+ *
+ * Exercise 4-
+ *
+ * Author: Kun Deng
+ */
+
+
+int main()
+{
+
+
+    return 0;
+}