diff --git a/days.c++ b/days.c++
new file mode 100644
index 0000000..bbd256c
--- /dev/null
+++ b/days.c++
@@ -0,0 +1,22 @@
+class Solution
+{
+public:
+    string longestPrefix(string s)
+    {
+        // approach1
+        int n = s.length();
+        string prefix = s.substr(0, n - 1);
+        string suffix = s.substr(1, n - 1);
+        while (prefix.length())
+        {
+            if (prefix == suffix)
+            {
+                return prefix;
+            }
+            else
+            {
+                prefix.pop_back();
+                suffix = suffix.substr(1, suffix.size() - 1);
+            }
+        }
+        return "";
\ No newline at end of file
diff --git a/matrix multiplication.cpp b/matrix multiplication.cpp
index 1f2fd1f..558a868 100644
--- a/matrix multiplication.cpp	
+++ b/matrix multiplication.cpp	
@@ -1,70 +1,41 @@
-#include <iostream>
+#include<iostream>
 using namespace std;
-
-int main()
-{
-    int a[10][10], b[10][10], mult[10][10], r1, c1, r2, c2, i, j, k;
-
-    cout << "Enter rows and columns for first matrix: ";
-    cin >> r1 >> c1;
-    cout << "Enter rows and columns for second matrix: ";
-    cin >> r2 >> c2;
-
-    // If column of first matrix in not equal to row of second matrix,
-    // ask the user to enter the size of matrix again.
-    while (c1!=r2)
-    {
-        cout << "Error! column of first matrix not equal to row of second.";
-
-        cout << "Enter rows and columns for first matrix: ";
-        cin >> r1 >> c1;
-
-        cout << "Enter rows and columns for second matrix: ";
-        cin >> r2 >> c2;
-    }
-
-    // Storing elements of first matrix.
-    cout << endl << "Enter elements of matrix 1:" << endl;
-    for(i = 0; i < r1; ++i)
-        for(j = 0; j < c1; ++j)
-        {
-            cout << "Enter element a" << i + 1 << j + 1 << " : ";
-            cin >> a[i][j];
-        }
-
-    // Storing elements of second matrix.
-    cout << endl << "Enter elements of matrix 2:" << endl;
-    for(i = 0; i < r2; ++i)
-        for(j = 0; j < c2; ++j)
-        {
-            cout << "Enter element b" << i + 1 << j + 1 << " : ";
-            cin >> b[i][j];
-        }
-
-    // Initializing elements of matrix mult to 0.
-    for(i = 0; i < r1; ++i)
-        for(j = 0; j < c2; ++j)
-        {
-            mult[i][j]=0;
-        }
-
-    // Multiplying matrix a and b and storing in array mult.
-    for(i = 0; i < r1; ++i)
-        for(j = 0; j < c2; ++j)
-            for(k = 0; k < c1; ++k)
-            {
-                mult[i][j] += a[i][k] * b[k][j];
-            }
-
-    // Displaying the multiplication of two matrix.
-    cout << endl << "Output Matrix: " << endl;
-    for(i = 0; i < r1; ++i)
-    for(j = 0; j < c2; ++j)
-    {
-        cout << " " << mult[i][j];
-        if(j == c2-1)
-            cout << endl;
-    }
-
-    return 0;
-}
+int main() {
+   int product[10][10], r1=3, c1=3, r2=3, c2=3, i, j, k;
+   int a[3][3] = { {2, 4, 1} , {2, 3, 9} , {3, 1, 8} };
+   int b[3][3] = { {1, 2, 3} , {3, 6, 1} , {2, 4, 7} };
+   if (c1 != r2) {
+      cout<<"Column of first matrix should be equal to row of second matrix";
+   } else {
+      cout<<"The first matrix is:"<<endl;
+      for(i=0; i<r1; ++i) {
+         for(j=0; j<c1; ++j)
+         cout<<a[i][j]<<" ";
+         cout<<endl;
+      }
+      cout<<endl;
+      cout<<"The second matrix is:"<<endl;
+      for(i=0; i<r2; ++i) {
+         for(j=0; j<c2; ++j)
+         cout<<b[i][j]<<" ";
+         cout<<endl;
+      }
+      cout<<endl;
+      for(i=0; i<r1; ++i)
+      for(j=0; j<c2; ++j) {
+         product[i][j] = 0;
+      }
+      for(i=0; i<r1; ++i)
+      for(j=0; j<c2; ++j)
+      for(k=0; k<c1; ++k) {
+         product[i][j]+=a[i][k]*b[k][j];
+      }
+      cout<<"Product of the two matrices is:"<<endl;
+      for(i=0; i<r1; ++i) {
+         for(j=0; j<c2; ++j)
+         cout<<product[i][j]<<" ";
+         cout<<endl;
+      }
+   }
+   return 0;
+}
\ No newline at end of file