diff --git a/project_euler/problem_11/sol1.c b/project_euler/problem_11/sol1.c
new file mode 100644
index 0000000000..315a7de5af
--- /dev/null
+++ b/project_euler/problem_11/sol1.c
@@ -0,0 +1,121 @@
+/**
+ * @file
+ * @brief [Problem 11](https://projecteuler.net/problem=11) solution
+ * @author [Vipul Cariappa](https://github.com/vipul-cariappa)
+ * @details
+ * Code to find the greatest product of four adjacent numbers in the same
+ * direction (up, down, left, right, or diagonally) in the given grid
+ */
+
+#include <stdio.h>  /// for IO operations
+
+#define ARRAY_SIZE 20              // size of gird
+typedef unsigned long long large;  // To hold product of numbers
+
+/**
+ * @brief Main function
+ * @returns 0 on exit
+ */
+int main()
+{
+    int array[ARRAY_SIZE][ARRAY_SIZE] = {
+        {8, 2, 22, 97, 38, 15, 0,  40, 0,  75,
+         4, 5, 7,  78, 52, 12, 50, 77, 91, 8},
+        {49, 49, 99, 40, 17, 81, 18, 57, 60, 87,
+         17, 40, 98, 43, 69, 48, 4,  56, 62, 0},
+        {81, 49, 31, 73, 55, 79, 14, 29, 93, 71,
+         40, 67, 53, 88, 30, 3,  49, 13, 36, 65},
+        {52, 70, 95, 23, 4,  60, 11, 42, 69, 24,
+         68, 56, 1,  32, 56, 71, 37, 2,  36, 91},
+        {22, 31, 16, 71, 51, 67, 63, 89, 41, 92,
+         36, 54, 22, 40, 40, 28, 66, 33, 13, 80},
+        {24, 47, 32, 60, 99, 3,  45, 2,  44, 75,
+         33, 53, 78, 36, 84, 20, 35, 17, 12, 50},
+        {32, 98, 81, 28, 64, 23, 67, 10, 26, 38,
+         40, 67, 59, 54, 70, 66, 18, 38, 64, 70},
+        {67, 26, 20, 68, 2,  62, 12, 20, 95, 63,
+         94, 39, 63, 8,  40, 91, 66, 49, 94, 21},
+        {24, 55, 58, 5,  66, 73, 99, 26, 97, 17,
+         78, 78, 96, 83, 14, 88, 34, 89, 63, 72},
+        {21, 36, 23, 9,  75, 0,  76, 44, 20, 45,
+         35, 14, 0,  61, 33, 97, 34, 31, 33, 95},
+        {78, 17, 53, 28, 22, 75, 31, 67, 15, 94,
+         3,  80, 4,  62, 16, 14, 9,  53, 56, 92},
+        {16, 39, 5, 42, 96, 35, 31, 47, 55, 58,
+         88, 24, 0, 17, 54, 24, 36, 29, 85, 57},
+        {86, 56, 0,  48, 35, 71, 89, 7,  5,  44,
+         44, 37, 44, 60, 21, 58, 51, 54, 17, 58},
+        {19, 80, 81, 68, 5,  94, 47, 69, 28, 73,
+         92, 13, 86, 52, 17, 77, 4,  89, 55, 40},
+        {4,  52, 8,  83, 97, 35, 99, 16, 7,  97,
+         57, 32, 16, 26, 26, 79, 33, 27, 98, 66},
+        {88, 36, 68, 87, 57, 62, 20, 72, 3,  46,
+         33, 67, 46, 55, 12, 32, 63, 93, 53, 69},
+        {4,  42, 16, 73, 38, 25, 39, 11, 24, 94,
+         72, 18, 8,  46, 29, 32, 40, 62, 76, 36},
+        {20, 69, 36, 41, 72, 30, 23, 88, 34, 62,
+         99, 69, 82, 67, 59, 85, 74, 4,  36, 16},
+        {20, 73, 35, 29, 78, 31, 90, 1,  74, 31,
+         49, 71, 48, 86, 81, 16, 23, 57, 5,  54},
+        {1,  70, 54, 71, 83, 51, 54, 69, 16, 92,
+         33, 48, 61, 43, 52, 1,  89, 19, 67, 48},
+    };
+
+    // to store present largest number
+    large biggest = 0;
+    large tmp;
+
+    for (int i = 0; i < ARRAY_SIZE; i++)
+    {
+        for (int j = 0; j < ARRAY_SIZE; j++)
+        {
+            // calculating product and checking against prest biggest number
+            // row
+            if (j < ARRAY_SIZE - 4)
+            {
+                tmp = (large)array[i][j] * array[i][j + 1] * array[i][j + 2] *
+                      array[i][j + 3];
+                if (tmp > biggest)
+                {
+                    biggest = tmp;
+                }
+            }
+
+            // column
+            if (i < ARRAY_SIZE - 4)
+            {
+                tmp = (large)array[i][j] * array[i + 1][j] * array[i + 2][j] *
+                      array[i + 3][j];
+                if (tmp > biggest)
+                {
+                    biggest = tmp;
+                }
+            }
+
+            // diagonal (towards down left)
+            if ((i < ARRAY_SIZE - 4) && (j < ARRAY_SIZE - 4))
+            {
+                tmp = (large)array[i][j] * array[i + 1][j + 1] *
+                      array[i + 2][j + 2] * array[i + 3][j + 3];
+                if (tmp > biggest)
+                {
+                    biggest = tmp;
+                }
+            }
+
+            // diagonal (towards down right)
+            if ((j > 3) && (i < ARRAY_SIZE - 4))
+            {
+                tmp = (large)array[i][j] * array[i + 1][j - 1] *
+                      array[i + 2][j - 2] * array[i + 3][j - 3];
+                if (tmp > biggest)
+                {
+                    biggest = tmp;
+                }
+            }
+        }
+    }
+
+    printf("Largest Product: %llu\n", biggest);
+    return 0;
+}