chore: add digitSwap program

digitSwap/main.cpp

@@ -0,0 +1,10 @@
+#include <iostream>
+#include <string>
+using namespace std;
+
+int main(){
+    string code = "";
+    cin >> code;
+    cout << code.substr(1,1) << code.substr(0,1) << endl;
+    return 0;
+}