diff --git a/ch_02/octal_converter/main.c b/ch_02/octal_converter/main.c
new file mode 100644
index 0000000..3883041
--- /dev/null
+++ b/ch_02/octal_converter/main.c
@@ -0,0 +1,254 @@
+/*
+ *
+ * Write a program that can convert a decimal to a hex value and vice-versa.
+ * The program must pass a command line argument to determine what will
+ * be the conversion type and the value to be converted. The value
+ * must be evaluated to make sure it's valid before converting.
+ * Otherwise, inform the user and terminate the program
+ *
+ * Author: Kun Deng
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+
+#define OCTAL 1
+#define DECIMAL 2
+
+
+// Returns 1 if octal conversion was chosen
+// Returns 2 if decimal conversion was chosen
+// Returns 0 or non-zero number if not valid
+int valid_conversion_option(char *option);
+
+// Returns 1 if valid and 0 if the decimal value isn't
+int valid_decimal_value(char *value);
+
+// Returns 1 if valid and 0 if the octal value isn't
+int valid_octal_value(char *value);
+
+// Useful in getting the length of a null terminated string.
+// Assumes that string is a null terminated string
+int size_of_value(char *value);
+
+
+// Converts decimal value to octal and prints the value
+void convert_to_octal(char *value);
+
+// Converts octal value to decimal and prints the value
+void convert_to_decimal(char *value);
+
+
+int main(int argc, char **argv)
+{
+    if (argc < 3)
+    {
+        printf("Provide two arguments: ./program [conversion_option] [decimal | octal value]\n");
+
+        return -1;
+    }
+
+
+    char *conversion_option = argv[1];
+    int result = valid_conversion_option(conversion_option);
+
+    if (result < 1)
+    {
+        printf("Invalid conversion option %s.\noct and dec are only supported\n", conversion_option);
+
+        return -1;
+    }
+
+    printf("%s is a valid conversion option\n", conversion_option);
+
+    switch (result)
+    {
+        case OCTAL:
+            if (valid_decimal_value(argv[2]) == 0)
+            {
+                printf ("Invalid decimal value %s\n", argv[2]);
+
+                return -1;
+            }
+
+            convert_to_octal(argv[2]);
+
+            break;
+        case DECIMAL:
+            if (valid_octal_value(argv[2]) == 0)
+            {
+                printf("Invalid octal value %s\n", argv[2]);
+
+                return -1;
+            }
+
+            convert_to_decimal(argv[2]);
+
+            break;
+    }
+
+
+    return 0;
+}
+
+
+int valid_conversion_option(char *option)
+{
+    const int OPTION_SIZE = 4;
+    // Supported conversion options
+    char *oct = "oct";
+    char *dec = "dec";
+    
+
+    int result = 0;
+
+    for (int a = 0; a != OPTION_SIZE; ++a)
+    {
+        // Checking to see if octal conversion is selected
+        if (option[a] != oct[a])
+        {
+            break;
+        }
+
+        if (a == (OPTION_SIZE - 1))
+        {
+            result = 1;
+        }
+    }
+
+    for (int a = 0; a != OPTION_SIZE; ++a)
+    {
+        // Checking to see if decimal conversion is selected
+        if (option[a] != dec[a])
+        {
+            break;
+        }
+
+        if (a == (OPTION_SIZE - 1))
+        {
+            result = 2;
+        }
+    }
+
+
+    return result;
+}
+
+int valid_decimal_value(char *value)
+{
+    int result = 1;
+
+    for (int a = 0; value[a] != '\0'; ++a)
+    {
+        // ASCII value 48 is 0. ASCII value 57 is 9.
+        // If value contains any non-numbers then
+        // the value isn't a valid decimal value
+        if (value[a] < 48 || value[a] > 57)
+        {
+            result = 0;
+            printf("Invalid character for decimal %c\n", value[a]);
+
+            break;
+        }
+    }
+
+    return result;
+}
+
+int valid_octal_value(char *value)
+{
+    int result = 1;
+
+    for (int a = 0; value[a] != '\0'; ++a)
+    {
+        // ASCII value 48 is 0. ASCII value 55 is 7.
+        // If value contains any non numbers or a 
+        // value greater than 7 then the value isn't
+        // a valid octal value
+        if (value[a] < 48 || value[a] > 55)
+        {
+            result = 0;
+            printf("Invalid character for octal %c\n", value[a]);
+
+            break;
+        }
+    }
+
+    return result;
+}
+
+int size_of_value(char *value)
+{
+    int size = 0;
+
+    for (; value[size] != '\0'; ++size);
+
+    return size;
+}
+
+
+void convert_to_octal(char *value)
+{
+    int value_decimal = atoi(value);
+    char octal_value[12] = "00000000000\0";
+    int index = 0;
+
+    printf("Converting %d to octal\n", value_decimal);
+
+   for (double quotient_decimal = value_decimal; (quotient_decimal >= 0);)
+    {
+        if (quotient_decimal == 0)
+        {
+            octal_value[index] = '0';
+            break;
+        }
+        else
+        {
+            quotient_decimal /= 8;
+            int trunecated_quotient_decimal = quotient_decimal;
+            double remaining = quotient_decimal - trunecated_quotient_decimal;
+            int octal_part = remaining * 8;
+
+            printf("Octal part %d index %d remaining %f\n", octal_part, index, quotient_decimal);
+
+            octal_value[index] = octal_part + '0';
+
+            quotient_decimal = trunecated_quotient_decimal;
+
+            ++index;
+        }
+    }
+
+   octal_value[index] = '\0';
+
+   // Swaps the values to match the octal format
+   for (int a = 0; a <= (index / 2); ++a)
+   {
+       char tmp = octal_value[a];
+       octal_value[a] = octal_value[(index - 1) - a];
+       octal_value[(index - 1)] = tmp;
+   }
+
+
+    printf("Decimal value %d is %s in octal\n", value_decimal, octal_value);
+}
+
+void convert_to_decimal(char *value)
+{
+    int octal_converted_to_decimal = 0;
+    int power_value = 0;
+
+    printf("Converting %s to decimal\n", value);
+
+    for (int a = size_of_value(value) - 1; a >= 0; --a)
+    {
+        int octal_part = value[a] - '0';
+        int octal_power = octal_part * pow(8, power_value++);
+        octal_converted_to_decimal += octal_power;
+
+        printf("Octal part %d octal power %d\n", octal_part, octal_power);
+    }
+
+    printf("Octal value %s is %d in decimal\n", value, octal_converted_to_decimal);
+}