[Add] solved solutions

cpp/FLOW004.cpp

@@ -0,0 +1,21 @@
+#include <iostream>
+
+using namespace std;
+
+int main()
+{
+    int t, n, i, fdigit, ldigit;
+    cin >> t;
+    for (i = 0; i < t; i++)
+    {
+        cin >> n;
+        ldigit = n%10;
+        while (n)
+        {
+            fdigit = n%10;
+            n = n/10;
+        }
+        cout << fdigit + ldigit << endl;
+    }
+    return 0;
+}