[Add] solved solutions

cpp/LUCKFOUR.cpp

@@ -0,0 +1,23 @@
+#include <iostream>
+
+using namespace std;
+
+int main()
+{
+    int t, i, n, sum;
+    cin >> t;
+    for (i = 0; i < t; i++)
+    {
+        cin >> n;
+        sum = 0;
+        while (n)
+        {
+            if (n%10 == 4)
+            {
+                sum++;
+            }
+            n = n/10;
+        }
+        cout << sum << endl;
+    }
+}